Intel ICH5R Raid Support

Hello,

i got a problem with a Asus P4P800S-E Motherboard and the Intel
ICH5R-Southbridge
Chipset. I configured Raid1 on the board and created a Raid Volume on the
two SATA
devices. After that i installed FreeBSD 5.3 BETA5 on one of the SATA devices
then rebooted
the sytem and everythings seems to work. I updated the system to RELENG_5
and rebooted
again but then the bootloader couldnt find a kernel.
Is there any known problem with the chipset and the raid functionality? If
there is, why could
the bootloader find a kernel by the first reboot before i updated the
system?

thanks for any hints!