Can I make a directory on OS X appear as a volume so I can backup using Super Duper? I use Lightroom and keep my library on an external hard drive. After I quit Lightroom I use SuperDuper! to back up that external hard drive to an identical external hard drive.

I also have two Transporters, one on-site and another off-site. I would like to backup to the on-site Transporter. The Transporter Library shows up as a folder. I would like to create a sub-folder and then use SuperDuper! to backup to that folder.

However SuperDuper only allows you to backup to a mounted volume.

Is there a way on OS X to make a directory appear as a volume so it would appear in the to: drop down of SuperDuper! or would the recommended way to be backup to a Sparse Bundle Disk Image located in the Transporter folder?
If you can share arbitrary folders on your Transporter you can then mount that folder across the network and SuperDuper will see it as a volume.

Failing that you may just want to create a disk image in that folder and have SuperDuper back up to that. That is how I do it with an external drive on a Mac that is always on. Several Macs back up to that drive, each to their own disk image via SuperDuper