Set up mirror after install?

[James Pifer]

I have a system I'm trying to rebuild. I have four 160 Gig WD drives all
of the exact model. I want to install FC5 using two drives and mirror to
the other two drives(I don't have a hardware IDE controller for
mirroring). I'll probably use LVM since I really want it to show up as
one big drive, ie approx 320 gig. 

The problem I'm having is I can't get the system to boot off anything to
run the setup. I've tried two types of external DVD's (basically
external enclosures) and although the boot menu sees the DVD drives, it
refuses to boot of them. 

I've also tried a flash drive, based on suggestions from another thread,
but I can't get it to boot off the boot.iso that is setup on the flash
drive. (dd if=boot.iso of=/dev/[flash drive])

Short of booting like this, can I setup the install on two of the drives
with the other two unplugged and a DVD temporarily plugged in? Then,
after the install, remove the DVD drive, plug in the remaining hard
drives, and then go in and somehow setup mirroring?

Any suggestions are appreciated. 

James