Default audio stream (1 Viewer)

[lyrad]

MediaPortal Version: 1.1.0 RC6
MediaPortal Skin: StreamedMP
Windows Version: Windows 7
CPU Type: intel ion 330
HDD:
Memory: 2gb
Motherboard: Asrock ion 330
Video Card: Asrock
Video Card Driver: Nvidia ion
Sound Card: Asrock
Sound Card AC3: Asrock
Sound Card Driver:
1. TV Card: None
1. TV Card Type: None
1. TV Card Driver: None
2. TV Card: None
2. TV Card Type: None
2. TV Card Driver: None
3. TV Card: None
3. TV Card Type: None
3. TV Card Driver: None
4. TV Card: None
4. TV Card Type: None
4. TV Card Driver: None
MPEG2 Video Codec: Mpc saf 4
MPEG2 Audio Codec: Ffdshow saf 4
h.264 Video Codec: Mpc saf 4
Satelite/CableTV Provider:
HTPC Case: Asrock ion 330
Cooling:
Power Supply:
Remote:
TV:
TV - HTPC Connection:

Can any of you clever people help a newbie, I have just setup my shiney new asrock ion 330 with the latest build of mediaportal and I am using saf 4 and moving pictures to play my mp4 collection.

The problem I am having is that all my collection has audio stream 1 as a mixed down stereo and audio stream 2 is Dolby 5.1, my question is is their a way of setting the mediaportal to default to audio stream 2 instead of having to press the green button or pressing a on the keyboard

I have searched and can not find the answer

Thanks
Lyrad