Bootstrapping Raid 5 w/GEOM

[Norberto Meijome]

Hi all,
I have a box with 4 x 120 GB EIDE drives which I want to convert to 
FreeBSD 5.4 ( it's an old SNAP 4500 from Snap Appliance, now owned by 
Adaptec, running a custom build of Linux)

I want to setup software Raid 5 , and I want it to affect ALL 
partitions, including / (so if any one of the drives fails, it will 
still boot up properly). I am planning on using GEOM, but open to 
suggestions.

I've been searching and cant find any pointers on how to set this up 
properly. I've been reading http://people.freebsd.org/~rse/mirror/ , but 
this is works for RAID 1.

Could anyone offer any insights / ideas / pointers (or step by step if 
you so feel inclined to :-) ) on how to set this up?

Thanks in advance,
Beto