Windows 7/64 MIDI problem

Hi,
I can't set the app to send MIDI to an external synth.
Is that somehow possible? The MS WMPlayer sends MIDI output to the ext. synth with no prob.

In I/O section the Use internel synth is cheched and it is not possible to check the "Use MIDI output" check box.
However if a uncheck the "Use internel synth" , then the "Use MIDI output" is automatcially checked but it doesn send anything to the ext synth. Yes, I restarted the app.

Any ideas?

Thanks