I know where you can look. First of all, I am NOT a UnrealScript kinda-guy --- I just play one in my dreams!
Anyways, if you look into the script PlayerPawn.uc, find the function, "CalcBehindView". This function is called from pretty much everywhere a behindview is needed. The function takes as arguments, your current camera "which is probably your eyes", your rotation (probably your orientation in space), and a distance to "pull back".
It might be possible to modify this function to add addition behindview functionality, but that is beyond the scope of my brain.
If you haven't exported all the script source files, you can find this script in the editor -- goto the Actor Class Browser and drill down the tree to Actor.Pawn.PlayerPawn, and then double-click it to bring up the script's source code. From there you can search for the CalcBehindView function. In my copy of UED2, when you search for something in the script source viewer, it doesn't bother to SCROLL to what it found, it just highlights your search results SOMEWHERE deep in the code - you have to manually scroll down to find it, or export the script to a REAL editor!
Hope this helps a bit,
BB.