Does the Heos show up in MC on the left hand side under Playing Now?
If so, you can just play straight to it as a zone. That's the most straightforward way. Then, I would probably set it up with a profile that sends PCM instead of the native format of the files. Most DLNA renderers support PCM.
If you have more trouble with this, you might post about it in the Media Network section of the forum. The people there will probably give you more help than you'd get here in the Mac forum.
Brian.