File size on removable disks

I installed REV drive and Backup Exec 10d on a Win 2000 SBS. Works great, but the files on the REV drive are 2Gb in size and there are 10 of them. I have changed the file size to 30Gb instead of 2Gb, but there are still 2Gb files on the disks. I have erased a disk and thought it would make 1 file the next backup, but it did not. I have set the media to overwrite. What changes do I need to make to have one file of 30Gb or less??
Steve