No,
you did not find the solution because it is too easy? I assume that you installed Slitaz to the MBR. Then you will have a file /boot/grub/menu.lst in Slitaz. As root open this file with leafpad
Shut the session. Login as root. Then type:
#leafpad /boot/grub/menu.lst &
Then you add the following lines after the Slitaz boot command:
title windows7 - sda1
root (hd0,0)
chainloader +1
boot
That works on my machine perfectly. @Trixar_za: apparently it has nothing to do with what Grub is installed, legacy or Grub2.
My slitaz boot command (hdd install) is like this:
title sliTaz 4.0 sda7 menu.list hier vmlinuz-2.6.37-slitaz
root (hd0,6)
kernel /boot/vmlinuz-2.6.37-slitaz root=/dev/sda7
boot