DCP-o-matic

I have a movie which was originally made with Dolby Stereo sound . It's a 3.1 sound matrix encoded in a 2-channel stereo track. Is there any way in DOM to tell the sound processor to correctly decode the track and play it via 4 channels (L,R,C, Surround)?

There is a simple Mid/Side Decoder in DCP-o-matic, which should work nicely with a Dolby SR encoded source. However, it will not decode to surround channels.