5.3b7 and ata raid1 - how?

Hi!

I'm trying to set up a new machine, from 5.3b7 ISOs.  This machine has a 
SiL 0680 based IDE RAID1 card in it, on which I have two 80Gb Maxtor drives 
- ad4 and ad6.

I have set up the mirroring in the IDE card's BIOS, however FreeBSD does 
not recognise the raid, instead presenting me with an installation target 
of ad4 or ad6.

This was the same under 4.10, however I just installed a minimum system on 
ad4, ran `atacontrol create RAID1 ad4 ad6` and re-ran installation, 
whereupon it spotted ar0 and offered me this as an installation 
target.  Under 5.3b7 this is not happening:  Although `atacontrol status 
ar0` reports READY immediately after creating the raid, after doing this 
and just rebooting into the minimum system again the same command shows 
Device not configured.

Is ata RAID1 therefore broken on 5.3b7 ??  This is straight off the ISOs 
downloaded a few days ago, so no custom options have been set, and the 
minimum system is just running GENERIC.

(5.2.1 failed to work at all, causing a kernel panic immediately after 
detecting the 0680 when booting from the CD or an installed system.)

Hardware is a Celeron 1GHz, M758LMRE motherboard (PC Chips?), AMI BIOS, 
plenty of RAM. There are TWO SiL 0680 cards present, but currently only the 
first has any drives attached. (This is to be a new fileserver, with 
multiple drives, although only the one RAID1 array is planned, for system 
and most important files.)

Any assistance would be most appreciated.

Rob O'Donnell.