backup exec 2010 R2 Disk to Disk to USB Disk

All

                I am new to the backup exec world. I am charged with making some changes to our current backup exec environment. We currently write everything to tape. We have setup an environment to go to disk. We want to be able to backup the data to disk and then move and/or copy it to USB but allow backup exec to control it so it does not lose track. We have a limited window to get the production backups done which is why we need a two step approach instead of writing directly to the USB drive which is slower. I already have the backups writing to disk. I need to know how I can also get those files to the USB drives. In effect we want an onsite and offsite copy of the data.

Thanks