use of system variable to specify paths

[sheepdog]

I would like to use in the configuration part :
configure->Preferences->Folders:

some system variables. I use Textpad usually from within the filemanager Total Commander. One advantage of this File manager is, that you can use a systemvariable %Commander_path% to specify the path you started it from.

So you could copy the whole Directory to another PC and work with iit - and with the programs in it's foldert.
This way I have a button to start TextPad with the Command: "%Commander_Path%\textpad\textpad.exe"

That for I would like to use as path for backups "%Commander_path%\Textpad\backup" but currently there is a folder '%Commander_path% created. The ".\backup" doesn't work too, because this way in each directory a directory 'backup' is created.

sheepdog