We believe that your issue has been closed by the upload of
Version 0.9.21 of grml-live from Michael Prokop <mika@grml.org>.
The explanation is attached below

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Format: 1.8
Date: Tue, 18 Aug 2009 00:33:48 +0200
Source: grml-live
Binary: grml-live grml-live-addons
Architecture: source all
Version: 0.9.21
Distribution: unstable
Urgency: low
Maintainer: Michael Prokop <mika@grml.org>
Changed-By: Michael Prokop <mika@grml.org>
Description: 
 grml-live  - build system for creating a Grml (based) Linux live system
 grml-live-addons - templates/boot/addons for grml-live
Changes: 
 grml-live (0.9.21) unstable; urgency=low
 .
   [ Michael Prokop ]
 .
   * New features:
     - Split the single /etc/apt/sources.list file into structured files
       in /etc/apt/sources.list.d/. We are using:
       - /etc/apt/sources.list.d/grml.list for all grml related repositories
       - /etc/apt/sources.list.d/debian.list for official Debian repositories
       [Closes: issue349]
     - Provide information about grml-live version and Debian/suite
       through /etc/grml_live_version in the generated ISO. [Closes: issue637]
     - New graphical boot menu. Can be disabled via ISOLINUX_METHOD=console.
     - New configuration variables DISTRI_NAME and DISTRI_INFO which should allow
       easier rebranding of grml-live based distributions.
     - Support installation of local files (not being part of any Debian package)
       through $CHROOT_INSTALL.
     - Display path of FAI logs during execution of grml-live.
     - Replace all references to ftp.de.debian.org with cdn.debian.org,
       see http://wiki.debian.org/DebianGeoMirror for details.
       Thanks for the idea, Marc Haber!
 .
   * Bug fixes and improvements:
     - When adjusting postfix configuration: make sure to execute newaliases
       command after adjusting configuration, otherwise the old hostname
       will be left inside /etc/aliases.db.
     - grml_cleanup_chroot: get rid of /etc/lvm/cache/.cache and
       /etc/lvm/backup/main as well.
     - grml_cleanup_chroot: drop the /usr/include/linux checks.
     - 90-update-alternatives: use wm-ng as default x-window-manager.
       [Closes: issue716]
     - Check for existence of $target/etc/apt/important_note.txt before
       operating on it.
     - buildd: drop GRML_LIVE_ARCH but instead use default architecture
       if not specified.
     - Set UTC=no by default. See http://bts.grml.org/grml/issue708 for
       details. Credits to Ulrich Zehl for debugging. [Closes: issue708]
     - Improve check for architecture which should be build: if not specified
       assume a safe default and check this one.
     - Unify variable default checks, always assume sane defaults.
     - Always run $SUITE checks, so grml-live repository is used also
       if suite isn't manually specified.
     - Detect existence of stage 'boot' using boot/isolinux so grml-live
       executed with options '-q -B' and empty boot/isolinux works as well.
     - Introduce $NO_WINDOWS_BINARIES which replaces $WINDOWS_BINARIES so
       we can improve sanity checks and easify configuration.
     - Integrate memtest86+ binary so we don't ship old versions from
       the build host. [Closes: issue717]
     - Check whether rebuild of ISO is needed even though the ISO exists already.
       [Closes: issue719]
 .
   * Debian packaging related changes:
     - Bump to Standard-Version 3.8.3 (no further changes).
     - Improve long description.
     - Update copyright file (make lintian happy).
     - Register grml-live html docs using doc-base.
 .
   * Documentation:
     - grml-cheatcodes: document bootoption 'nostartx'.
     - Apply patch from Marc Haber (thanks!) for new grml cheatcodes
       (new DCS directory feature).
 .
   * Software related changes:
     - Add git-email to GRML_FULL (thanks to Joerg Woelke for mentioning).
     - Add aesfix, aeskeyfind, bios-memimage, chaosreader, ext3grep, fatback,
       myrescue, pipebench, safecopy, shed and xmount to GRML_FORENSIC. The
       packages are either already available or should be available soon.
     - Add scsitools to GRML_MEDIUM.
     - Drop bar from GRML_FULL (no release since 2007, consider using
       for example cpipe instead).
     - Drop grml-saveconfig as it is replaced with recent versions
       of grml-autoconfig.
     - Drop hydra from GRML_FULL (the license is not a clean GPL one).
     - Drop icedax from GRML_FULL (we have schilyutils available).
 .
   [ Thorsten Glaser ]
   * Update MirOS bsd4grml to 20090812 and sync menu.lst, grub.cfg,
     isolinux.cfg, syslinux.cfg with each other; provide a fallback
     way to boot MirOS bsd4grml from both GRUB versions using modules.
   * Fix going back to GNU GRUB from ldbsd.com via alternative boot method;
     while here, add the grml release info to the appropriate file.
Checksums-Sha1: 
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 42adb242989a5292e025bcb63a9cf8248479031e 7860636 grml-live_0.9.21.tar.gz
 7363f2ccb35825ee3f0d0997f030fc12becf1810 1076508 grml-live_0.9.21_all.deb
 b50ae9087ec9c12f62802986a40569a05a3103e2 6812728 grml-live-addons_0.9.21_all.deb
Checksums-Sha256: 
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Files: 
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 cf64034ed0e3246ee3bb4d3ef5e9e352 7860636 grml extra grml-live_0.9.21.tar.gz
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Fixed in git:

http://git.grml.org/?p=grml-
live.git;a=commitdiff;h=80c5fd2;hp=85c10ba4c34c04a977ae4358e1506f2ecc819c34

In autoconfig.functions, the logic assumes that the Hardware Clock is set to the
local time only if one of the following is true:
* an explicit "localtime" boot parameter is given
* UTC=no is set in /etc/default/rcS
* the variable UTC is not contained in /etc/default/rcS at all

# {{{ Set clock (Local time is more often used than GMT, so it is default)
config_time(){
    [...]

    # The default hardware clock timezone is stated as representing local time.
    UTC="--localtime"
    grep -q "^UTC=" /etc/default/rcS || echo "UTC=no" >> /etc/default/rcS
    checkbootparam utc       >>$DEBUG 2>&1 && sed -i "s|^UTC=.*$|UTC=yes|"
/etc/default/rcS
    checkbootparam gmt       >>$DEBUG 2>&1 && sed -i "s|^UTC=.*$|UTC=yes|"
/etc/default/rcS
    checkbootparam localtime >>$DEBUG 2>&1 && sed -i "s|^UTC=.*$|UTC=no|" 
/etc/default/rcS
    grep -q -i "^UTC=yes" /etc/default/rcS && UTC="-u"

    [...]
}
# }}}

Unfortunately, grml-live's GRMLBASE/18-timesetup script explicitly sets UTC in
rcS to whatever value it's set on the buildserver, which appears to be UTC=yes.

# tell if hwclock is running in UTC or local time
if [ -n "$UTC" ] ; then
   echo "Setting hwclock parameter UTC to $UTC"
   sed -i "s|^UTC=.*$|UTC="$UTC"|" $target/etc/default/rcS
fi


Therefore, there appear to be three options to address this to me:
1) Start grml with the localtime boot parameter by default
2) Remove the above 5 lines from 18-timesetup
3) Rework the logic in so it ignores the setting in /etc/default/rcS while booting

If you tell me which option you prefer, I'll come up with a patch for it.

Additionally, the boot parameter "localtime" isn't documented in
grml-cheatcodes.txt. If this is unintentional, I'll try to prepare a patch for
it as well.

Booting with "tz=Europe/Vienna" doesn't seem to have any effects. We should 
investigate on this issue (once more, yes I hate all this locale and timezone 
crap).