How do I enter a UNC path?

I've inherited a Win2k3 server to look after with True Image Echo Enterprise Server 8.0 installed.

I set a scheduled backup task to run on a mapped network drive, but the task failed with "file not found" and "there is nothing to backup" error messages. Further investigation on the Acronis website tells me that it doesn't support mapped drives and instead, the user should enter the UNC path. Ok, no problem, but when you go through the wizard to create a backup there is no option to enter a UNC path. You only get a choice of drives. I've even tried a UNC path under 'My Network Places' but it doesn't allow you to open it up and drill down to files and folders under the selection as though you were navigating using Windows explorer. Does anyone know a way to spercify a \\server\share path in this version of the software?