SSG with DLNA between VPN

Hello, 

We are installing Juniper SSG 320M in different sites, and configuring  VPN GRE between them, also We are trying to send multimedia data, through the tunnel of the VPN, with DLNA without success, We are configuring a igmp proxy host mode on the interface where the server of dlna is connected, create a igmp proxy in router mode where the client of dlna is connected and also create a multicast policy from server zone to client zone igmp bi-directional. 

Do we need to configure something else?  Does anyone have a configuration guide to make it work through a tunnel?  It is possible send multimedia data with DLNA through VPN GRE?

Thanks