|There is no raid level that mixes hardware and software raid.|
You cant' do hardware raid 0 and software raid 1 and say its raid 0+1 because 0+1 is a hardware config.
Tell your friend nice try. :-)
The setup will work and is working except for the risks I detailed for you in my first response.
The best you could do alternately is to raid5 the three disks but you would only be using 160 gig of the 320 gig drive
Raid 5= (1)160+(2nd)160+ 160 (out of 320)= (1)320gig volume
Hardware raid requires each disk to be the same size or if larger you can only strip according to the smallest drive.
Hardware wise this would have been your best option.
Concerning your question "Could one partitioned the 320 to = 2 /160 ?"
Hardware raid is a level below partitioning [like formatting is above partitioning] and has nothing to do with hardware raid.