Invoking MP3Tag from another program

Hi All,
I am struggling with a way to invoke MP3Tag from within another program ("Beyond compare" V. 4.3) for a simple one-file tag editing job. (similar to explorer's context menu functionality). I keep getting an "access denied". Is this some elevated command prompt devilry?

Is it at all possible? If so, how? Any help would be most welcome!

Could not find any documentation on MP3Tag's command line parameters but I have found an old thread about Florian's unwillingness to tackle that. Is it still valid?

See the help for command line parameters:

Aah -- Why do I always only discover things when you are pointing me there? :blush:
Thank you again, Ohrenkino -- you are a wonderful help!