(self-made)pluggo plug - no sound output in Logic

Hello,

I made a little pluggo plug on MacOSX.
As VST it functions flawlessly, but as AU there is no audio output. as the meters are working I assume there is Audio input, but it does not get out of pluggo runtime as an AU.

Pluggo Runtime 3.5.4/MaxMSP 4.57

Any insides?

Thanks,

best