Laszlo .Laszlo

Unfortunately that’s not possible.
But if you put one channel track (can be silent track) to next to the midi file (use the uTool for exportinng the song) that should be working. You can easily can generate empty mono file ie with the Audacity.
Please make sure, the audio file is a same length with your MIDI file, because the playback will be stop at the end of the audio file.