do you work for motorola??
anywho - the controller (Promise PDC20267) is what i am guessing is the issue, why i am not sure, it looks like the kernel at time was being patched to support that controller. see here: ->
http://seclists.org/lists/linux-kern.../Sep/0709.html , which kinda sucks because wirk began on it back in pre 2.4 days. ahywho - i am guessing redhat 8 was patched properly. it may be easier making that compatible with your program than 7.3 support you hardware.
also, is there another controller on the board, if so you probably hook teh dirver up to that, install rh 7.3 which should work with the chipsets controller, then if you wish install a new kernel and then move the drive to teh promise controller.