I do not have idea why this very useful option is removed from sarge. Now i always need 2 cd's, sarge and woody with xfs. In my opinion it's the worst change from woody to sarge.
Full rescue support was not integrated into d-i by the time sarge was released.
The latest Installers have a rescue option: """ Rescue with post-Sarge daily built imagesThe post-Sarge daily built images have a new rescue boot option. This will use the first part of the installation process to set up a working system, ask you to select the device that holds your root partition, and will then mount that partition and chroot to it. Note: you will need to mount any other file systems (including proc) manually, despite what 'mount' will tell you.
"""It should be available for etch.