I've purchased a Sig556SWAT and I'll be picking it up when I return to the states in about two months. I want to be able to mount my M9 bayonet and I noticed that the quad-rail fore-end uses the small lug hole on the bottom of the gas block. The lug attachment which allows mounting of the M9 bayonet uses the same hole, thus only allowing you to mount one or the other.

Is there another way to attach a bayonet lug that I am unaware of, or are you just outta luck if you prefer the quad-rail over the classic fore-end?