>2TB Disk partitioning with kernel 2.6.8.1 problems

Hello,
I've been beating my head over this all week now.
Here's my setup:
Promise vt15100 with 15 400GB disks (newest firmware)
1 Raid5 array of 13 disks ~4.5TB
RedHat 9.0 upgraded to kernel 2.6.8.1
Adaptec 39160 with latest firmware.

I've finally gotten it to the point where all 4.5TB are recognized by
the array, scsi bios, and os level scsi driver.
Large BD support is compiled into the kernel.

My problem is: I can't create a partition no matter the utility I use.
fdisk complains about cylinders not being set. sfdisk doesn't see but
8MB or so.

I've searched everywhere but haven't been able to find a solution.
Maybe I've missed something obvious, so please feel free to smack me
with the clue stick, just tell me how to get this running!

Thanks,
Sean

PS: Working with Promise Technologies tech support has been an
absolute nightmare. We'll probably be staying away from their products
in the future. Too late now for this one.