So you are saying you do have the Apple Pro RAID card? Yes?
And you have the system on the RAID only?
Have you thought to clone 10.7.x to a single drive, update and then restore?
With any RAID you want alternate boot drives, and I'd leave the OS on one of the two ODD SATA ports and not connected to a card. In fact I would ditch the card.
Someone found out that there was a firmware update for theirs but odd Apple only shows the firmware if the OS was something pre-Lion.
Also I am a fan of rebuilding from scratch any drive or array with a new OS or when there are changes - though not from 10.7.4 to .5 unless it impacts arrays and that card.
So use CCC along with TM - I would never use just TimeMachine for backups, and make sure you have and can boot 10.7.x and not touch the old system.
format a disk drive and do a clean install of Lion.
And buy a copy of carbon copy cloner and start using that...
Create an OS X Lion Install disc
How to clone your system:General purpose Mac troubleshooting guide: Isolating issues in Mac OS X
Creating a temporary user to isolate user-specific problems: Isolating an issue by using another user account
Identifying resource hogs and other tips: Using Activity Monitor to read System Memory and determine how much RAM is being used
Starting the computer in "safe mode": Mac OS X: What is Safe Boot, Safe Mode?
To identify potential hardware problems: Apple Hardware Test
General Mac maintenance: Tips to keep your Mac in top form