Problem to install 5.2.1 on SATA disk chipset VT8237

[pl.smith at free.fr]

Hi,
Freebsd Release 5.2.1

i've bought a Gigabyte GA-7VM400MF-P with the chipset VIA KM400 and VIA VT8237
for the controller
i've harddrive on the sata controller, and boot sysinstall from the cdrom, all
start well but the harddrives aren't recognized..?
there is no disks...
so after, i've tried this trick:
i've installed freebsd on the harddisk attached to the ata controller and reboot
with the hardrive on the sata controller, but it doesn't work ...

Someone has got another the solution ? why freebsd doesn't recognize the SATA
disk in my case ?

thanks.