How to Repartition a Hardware RAID1 Array?

Hi,
I built a new system about a year ago, including a legit copy of XP pro and
well-equipped ASUS A8V MB. To complete the upgrade, I built a hardware IDE
RAID 1 with 2 160G Maxtor HDDs using the promise FastTrak controller and
firmware.
Now for my mistake - I partitioned this drive to allow for easy reinstall of
the OS, into 4 parts - OS, Installables, SW, and Data at 8, 50, 13, and 79
GB, respectively.
In spite of my best efforts to keep all SW installations on the SW drive, Im
now at 98% occupancy of the OS drive and must repartition it. I can find no
written information on what software to buy and/or what to do to make this
process have more than a 20% likelyhood of completing successfully without
data loss. I've tried XP internal features and Acronis Partition Expert to
no avail. I tried breaking the mirror by removing power from one drive of
the pair, but no boot.
Is anybody out there a real RAID expert for a configuration like this???
--
Bob in Florida