I've used Partition Magic 7.0 to copy a RAID drives contents to a single fixed drive, then it can be imaged any way you please. I did have problems doing this on systems with the High Point 370 controller. The copy operation would just stop at around 50%.
If you want to image a RAID drive for backup you can hook up any spare drive with enough capacity to an open IDE port, use Partition Magic to delete any partitions on the drive and copy the RAID drive's partition(s) to the unallocated space on the spare drive. If the source RAID drive is a boot drive, remember to set the copied partition active. You can now change the boot order in the BIOS, boot from the spare drive and restripe your array drives if you wish. After you have set up a new array, use PM to copy the spare drive's contents back to the RAID drive (set it active) and youu can now boot from the RAID drive again. Keep the spare drive as a backup in case the RAID array bites the big one.