Upgrading RAID 1 to larger drives...

My server has (4) 250 gb hard drives, (1) is always in it and every week another gets swapped in to rebuild. I'm pretty much out of space and I need to upgrade.

I'm using a Promise TX4310 raid controller and the WebPAM software to manage it. I bought (4) new 640 gb hard drives to upgrade to, but no matter what I do I cannot get the raid to work after the fact.

I have tried cloning the drive, but to no avail. I have successfully created the RAID again on (2) blank drives, but when I put the disk image back onto the drive the RAID is lost or something.

I could really use some help, as I've been at this for almost 20 hours. Is there a detailed process that I can follow to upgrade the drives or should I just start over on a fresh drive with a fresh copy of Server 2003 and then just copy the necessary files back over? I would like to avoid this as there are a lot of settings and a lot of installation that would have to happen. Any help would be greatly appreciated and if you need more information I would be more than happy to send it. Thanks in advance.