It is just cutting/copying and pasting any TEXT you have highlighted within a file, and it does it fine, but that is very insufficient.
The same comes true with Vnc or whatever you like:
in all instances, you can transfer files, but by a separated process, not just the file you highlight during a remote connexion, and this is, i agree with you, a pain in the ......
I used (both LAN have dynamic ADSL adresses) to connect from one to the other via No IP dns names.
More for security reasons then just for copy/paste, i do it from today through a Hamachi VPN connexion (http://www.hamachi.cc/), and that becomes miraculous:
now, i connect radmin via the Hamachi virtual adress and i can, either directly with Hamachi, or via the Network Neighborhood, explore the remote files exactly as if they were on another logical drive or PC of the same LAN.
Including cutting and pasting whatever file format i have decided to.