Cubase 7.0.6 External Instrument MONO not working ?

Hi,

In VST connections I create External Instrument “Moog Sub Phatty”, with mono input (In 3 to my RME FF400). When adding ‘Instrument track’ with “Moog Sub Phatty”, Cubase warning that:

This mixer configuration expected “Moog Sub Phatty” to have Output 1: Stereo,
-> The instrument currently has Output 1: Mono
-> The instrument channel will be silent.

Is there a posibility to make MONO compatible External Instrument ?

Anyone working with Cubase and external (monosynth) instrument ?