First of all, crypto needs to be done using newt ("install", not installgui). This is a known limitation of debian-installer and documented somewhere on the d-i website. Secondly, when installing from something involving an iso image, d-i will load the...
When installing from something involving an ISO image, d-i will load the wrong loop module and later on setting up loop-aes will fail. After generating enough randomness, you will receive the message "An error has occured while configuring encrypted volumes",...
If you are trying to use SSH inside a debian-installer session, you might run into some problems... With the installer from lenny, ssh will complain about a missing libz.so.1. I couldn't find this file anywhere on the media, it is...