That's a right pain in the arse then, not sure what else you could do to solve it, I have heard of some law that states if a piece of music is altered (enough) more than 10 times it is considered no longer a sample and therefore is exempt from copyright, not totally sure if it's completely true, but maybe something to look into, if not for this project then one in the future. If that's just crap I'll be putting it to those that told me as they work in the music industry!
Good luck with whatever you decide, it would look great if even silent!