I am having a little bit of trouble trying to find the best way to triple boot my MBP. Previously I had it set up running Fedora 13\OSX\Win7 and recently I decided I would like to run BT4r2. After removing fedora and fixing my partition scheme I have not been able to find a good definitive guide on how to install Backtrack to a single partition without resizing or touching the others. I have my drive partitioned and created a new ext3 linux partition for backtrack using fdisk from the live CD. If I mount this newly created partition using something like:
mkdir /mnt/bt4
mount /dev/sda4 /mnt/bt4
And then proceed to run the installer, it does not show anything in the partition screen after selecting my keyboard type. If I simply un-mount the partition it shows all of the partitions in the installer. I don't see a simple option to select the preformatted partition that I have ready for backtrack to install to.

My current partition scheme is:
/dev/sda1 GPT
/dev/sda2 Unknown (HFS+ Mac OSX)
/dev/sda3 NTFS (Windows7)
/dev/sda4 Linux