[CentOS] How to remove Microsoft soft raid?

Have a quad core workstation that was running WinXP_64 that I want to
blow away and install CentOS 6.  C6 install process finds raid metadata
associated with sda and sdb, and then excludes them from the rest of the
installation process.  

There doesn't appear to be an option for disassembling the raid as part
of the install process.  I think there should be.

Any tricks to removing/by-passing the soft raid left over from the
previous OS?

Dave M