Confused with your question, the Reynolds Assults are Campag, but you have a Cannondale CAAD 10, which is stock SRAM with Shimano RS10's

Are the RS10's faulty? does the hub need a new freehub?

If you need a new freehub body for the RS10's the only option is to use a Shimano one.

Are you trying to use the Reynolds wheels with the SRAM / Shimano setup?

SRAM / Shimano cassettes only fit SRAM / Shimano freehubs, Campagnolo only fits Campagnolo.

The only way the Reynolds wheels will take the SRAM PG-1070 cassette is if you can change the Campag Freehub to a Shimano one, Reynolds may be able to supply this, you can check their website for that.