add drive to raid 5 array on DL360 G5 P400i

I would like to add a drive to my existing raid 5 volume, but there doesn't seem to be any options for "expand array" or anything like that.  It's a win 2003 x86 server with the BIOS + firmware updated for the mobo, array controller, and HDs.

I couldn't see either option in the GUI or the BIOS utility, does it need to be done through the CLI?

Thanks,

j