I'm using the Asus A7V under Win2000Pro also with the latest VIA's installed. Under IDE ATA/ATAPI controller I have a Primary IDE Channel, Secondary IDE Channel, and VIA Bus Master IDE Controller. Under the first two, it says Ultra DMA Mode (DVD and CDRW drives).
Under SCSI and RAID controllers the Win2000 Promise Ultra ATA 100 controller is listed but it doesn't have an advanced settings tab. So I guess I'm in the same boat you are trying to figure out it my hard drive is operating with DMA switched on...