Sata/IDE drive recognition problem

[Vizion]

Hi

While preparing to move a system from i386 to amd architecture The existing system is dual booting i386 for 5.4 stable and 6.0. My plan is to remove both systems, preserve my data and reinstall 6.1 amd from cd.

The motherboard is a FA-K8N51GMF-9 with 3 hard drives installed. 2xSata and 1xIDE.

Freebsd 5.4 
#df sees 
/dev/ad4s1a 
devfs, 
/dev/ad4s1e
/dev/ad4s1f
/dev/ad6s1d
/dev/ad6s1e
linprocfs

Freebsd 6.0
#df sees
/dev/ad0s1a
devfs
/dev/ad0s1e
/dev/ad01f
/dev/ad0s1d
/dev/ad4s1a
/dev/ad4s1f
/dev/ad6s1d
devfs

The CD installer select drives interface for 6.1 RELEASE amd64 recognizes
ad0 and
ad4 
but not ad6.

For installing 6.1 amd I will need the installer to see all physical devices and existing partitions. 

The Bios CMOS features show 
IDE Channel 0 Master WDC WD2000JB
IDE Channel 0 Slave Lite-on CD-RW
IDE Channel 2 Master ST3160827AS
IDE Channel 3 Master WDC WD2000JD
The Advanced Bios features show
First boot device CDROM
Second Boot Device Hard Disk
Third boot Device Hard Disk

The Hard disk boot priority sequence options show:
Ch0
Ch2
Ch3 
root
shutdown -r

/var/log/messages shows
ad0 WDC WD2000JB at ata0-master UDMA33
acd0 Lite-on at ata0-slave USMA33
ad4 ST3160827AS at ata2-master UDMA33
ad6 WDC WD2000JD at ata3-master UDMA33

How do I get the installer select drives interface to recognize ad6?

Thanks in advance

david