Lion Xsan RAIDS and Open Directory Server or Active Directory Domain

First here is the setup...

I will have a a Xserve 4 Macs with each a fiber card two Promise RAIDS and a fiber switch
Okay all 7 devices will be linked up over fiber a course... But my question lies in Lion and Xsan!
Do I have to bind the Xserve (which will be lion) to a Open Directory Server or Active Directory Domain to have Xsan to function? Cause the it guys don't want a another Open Directory Server or Active Directory Domain on the network do to there windows boxes.

Thank you.