So, I read this somewhere else and it might have been on here but I can't remember so I tried it it and it worked so here is what to do.
Go to http://www.PlayOn.tv and download their their software for the free 14 day trial. Install the software and follow the setup procedure. You might also have to make a change to your Internet Firewall but maybe not.
Go into Boxee under Media Sources and you will see the PlayOn UpnP server. Select it and addit as a media source and your done.
The kicker is it's $39 dollars for a year after the trial runs out but it nice to fall back on if Boxee doesn't come through with the goods.