Please help!

[lucy-the-kitten.livejournal.com]

Hi!
  I had posted before about this problem (post here). I bought some goth pants for my boyfriend. He wears a size Extra Large, and the pants are a size Large. I figured id just let them out at the seams and kinda add to the waistband, unfortunately, the seam allowance is maybe 1/4in. and its double seamed. also, the pants are the kind with the zip-off bottoms, so they turn into shorts. and they have big cargo pockets over the side seams, and some other little decorative thingies (studs and d-rings). i really need some help with this. Hes so excited about the pants, and he loves him, he looked so depressed when he put them on and couldn't button them. (man did i feel like an ass.)
  heres the closest i could find to the pants: pants here 
 any help at all would be totally awesome and ill be your best friend forever! thanks so much!