You need to use the 'planar map' function along with edit faces in the modifiers box IIRC, you select the faces from the side, then hit planar map, and the selected faces will appear from an average side view in the UVX map box...
Ok, thats the worst explanation ever. I believe its the correct method though... and there was a tutorial somewhere...
Damn, Im too tired to think, sorry i cant be any more help
edit:
http://killasmods.game-mod.net/tnkskn3.php
that details the method im speaking of!