Arcserve 11.5 help

I have Arcserve 11.1 SP2 installed on my Netware 6.5 SP8 server. This box has a huge Groupwise install on it that I need to backup. This is the only server that I have that has this amount of data. Apparently Arcserve 11.1 SP2 does not give you the option to backup to anything but the tape. This is my major problem right now, I have so much data that it fills up multiple tapes and causes the server to run really slow. Since I have a license for 11.5 SP3 I wanted to find out if I could do the following:

1) Install it on a Netware 6.5 server
2) Backup up to something besides tape

Thanks for any advice! It is greatly appreciated!