Mac OS 10.4.11 Server and mirror RAID


Hello folks,
Several months ago, when I take my 1st Mac (G4) it's came with 1HDD (80GB). Than I decide to install Mac OS server version (10.4.11), so I make 2 partition - one for current OS (10.4.9) and one for server OS (10.4.11).
Now I bought another 80GB HDD and want to build two HDD's in mirrored RAID.New HDD was formatted and prepared for the RAID.Screenshot:

To make this RAID I use this guide, but... I can't add a whole drive for source, only partition from it (Macintosh HD or server ).

Is there a way to make full mirror of my boot HDD (this one with 2 partitions) and copy this mirror to my 2nd HDD?