Running Pianteq 5 simultaneous with Transcribe

I just downloaded the trial- version of Pianoteq Stage and it plays / sounds nice with my VPC1.

My set- up is as follows;

Fujitsu Q900 pc
Kawai VPC1 controller
Behringer USB Sound- output to mixer.

I have tried to run Transcribe (a (mp3- ..)soundfile- playback program) simultaneous with Pianoteq 5.
I would like to hear both programs sounding on my headphone.
that only seems to be able when I set the configuration on 'Windows'
When I use 'Windows direct' or 'Asio' only pianoteq is sounding.

The problem is that when I use the 'Windows' option, I can hear both programs sounding simultaneous,
but a big latency occurs while playing.

Is there some simple solution to solve this problem?

Thank you.