I have a project I've been working on, and I need to have a .deb package I made wrapped into my preseeded ubuntu install disk. I know that late_command should be my saving grace, but I have tried everything I can think of such as:

d-i preseed/late_command string apt-install mydeb.deb
where mydeb.deb is in the base directory of the CD rom (not in a folder, didn't know how else to put it) I just really need to have it installed.

Please help!

Many thanks