I need help skinning a jean material

So I’m reskinning a PMC model to seem more personal,
but I’m finding it impossible to reskin his legs to be wearing jeans instead of cargo pants

If anyone has any spare time at all, I’d really appreciate them just doing this for me. Or even giving me some tips on how to do it myself, I’ve tried tutorials but it’s no help.

http://www.filefront.com/15847849/GSAAA.vtf