Migrate harddisk with FreeBSD into new machine

[C.M. Burns]

Hi list,

I have a problem. A faulty machine was running freeBSD with a two 
harddisk software raid.
now these two disks should be put into a new machine, but of course it 
won't boot because it is new hardware.
Kernel just reports: cannot mount root device from /dev/mirror/gm0s1a 
(or sth like this).

question is now, how can i add the correct driver into the initial 
ramdisk (if there is such a thing on bsd) so the machine finds the two 
drives?
second question: how can i afterwards remove the software mirror and 
only use one harddisk from that moment on?

any help is very welcom, as i have no idea about bsd. i am a linux guy ;)

thanks!