RH73 using raid1

I installed RH7.3 on a testserver with raid1
using 2 IDE HD's. Everything is working fine.

If I remove the primary IDE HD and try
to boot the server from the secondary
master IDE HD it won't boot.
(not even the bootloader is starting)

I assume this is because the booloader
(in this case Grub) is not installed in
the MBR of the HD on the secondary IDE channel.

How can I install Grub in the MBR of the 2nd HD
of my software raid1?

Christian