Install Backtrack 5 r2 into running LUKS setup installed with ubuntu

One hard disk (sda), two partitions, with a working Ubuntu running. 1) /boot 2) LVM with this virtual volumes/partions/ or whatever they are called inside: 1. Swap 2. Ubuntu 3. Home 4. Prepared for Backtrack Of course I would like to share home and swap. I have seen tutorials, but they look outdated and complicated and they are for setting up everything just with backtrack. It seems you have to do some things manually after backtrack install to get it running with LUKS. I like to know what it is exactly that backtrack don't do automatically and how to install backtrack in my prepared partition. I want to tell backtrack NOT to install a boot-loader (I think it's possible) and setup the grub from Ubuntu to be able to boot backtrack.