Hmm, not sure, I keep LinuxMCE away from my RAID. I use separate drive to install LinuxMCE to and use 4x1TB drives in RAID + LVM setup. I just don't trust any automated system to touch my data. I like to take care of my data so I they get mangled I have no body to blame but myself.
But I'll be also trying to learn more how LinuxMCE does raid and see if I can add LVM support into lmce. Until then I hope somebody who know more can help.