Here is another option for you, that worked for me. Please excuse any errors since I did this quite some time ago:
1) Disconnect the two additional drives
2) Install SME to the first drive
3) Reconnect the second and third drives
4) Use fdisk to create your partitions
5) Run mke2fs to create the file systems on each disk
6) Create directories on your first disk, hda (i.e. /hdb and /hdc)
7) Edit the /etc/fstab file and point the hdb1 mount point to your /hdb directory and the hdc1 mount point to /hdc

Create the necessary sub-directories under the /hdb and /hdc
9) Create symlinks to the directories on hdb and hdc
If anyone see's any problems with this please jump in.
Hope this helps!
Tom Carroll