You can install updated vlc 1.1.10 easily with the use of an Ubuntu vlc ppa added to your system sources file. I have done this with BT5 gnome and built ucsniff with all options except debug without issue.
Commands to add ppa source
you can then install updated versions of vlc and libvlc which will work with ucsniff to build it with live video support. This ppa does have other things in it but nothing I see should break anything else in your backtrack5.
Hope that works for you.