Attaching the Rifle Stock

Hey All....I was looking for some thoughts on this one. I got heavy rifle stock that I need to attach to my blaster. I actually bought it off of someone and he never attached it. But I really would like to complete it. The gun itself is a plastic toy guy, which has very cool lights and sounds when it fires. I would love to be able to keep the sounds but if it has to go it has to go. I guess what I am asking is how to attach this plastic stock to light plastic gun with out breaking it?

got pics?

I don`t know if this is what you want to do, but it may help...........

http://www.thedentedhelmet.com/f20/scratch-ee-3-new-pics-8170/