MLOK? If so, you can get a long MLOK-Picatinny rail section that can hang past the end of the handguard to get your positioning correct.
Or if it's not MLOK, is there another type of add-on Picatinny that works with your handguard?
You'd need the Picatinny adapter from Magnetospeed as well.
Otherwise there are 3rd party custom solutions, like this:
But the Picatinny solution would be the cheapest if it works for you.