Howto play video with external audio in Silverlight?

Is there any proper method to play synchronously video and external audio, other than simply having two MediaElement (one for video source and one for audio) started simultaneously? I need to play video开发者_如何学C with different soundtracks, but I belive that just two separated MediaElements will be out of sync at some point of time. Maybe there is some way to add audio source to the existing MediaElement with video? Platform: SL3, but SL4 will be good as well.

Thanks in advance.

This project provides "support for multiple audio tracks" which sounds like it will do what you want: http://smf.codeplex.com/