Freehub swapping is the coolest thing since key parties. If you've got Reynolds' DV3K (except 2008 which used DT sourced hub), Assault, Attack, Solitude, or Strike rear wheels and you're looking to change your Campagnolo compatible freehub body for a Shimano/SRAM compatible freehub body, this is the style of freehub body you'll want.

Swapping them is pretty easy. Insert a 5mm Allen key into the left side of the axle. Insert a 5mm Allen key into the right side of the axle. Turn the right side Allen counterclockwise until it completely unscrews. This can be done with the cassette on or off the freehub body. Pull off the current freehub. Insert the new. If you think the axle needs a little grease, go ahead and put a little on. Reynolds uses Super Lube, but you can use whatever. When the new body is pushed fully on, get that right side nut, place it atop the threaded axle end, and with with your 5mm hex keyWant to turn clockwise until it is snug. If your freehub body arrives with an extra rubber gasket, you can toss it. This piece is only needed if you have loose ball bearings- pretty much a thing of the past.