I have a Cisco UC520 with an external source (using external port) for MoH (Music on Hold). The MoH works perfectly on handsets directly connected to the UC520. However I have a remote worker that is unable to hear any MoH and instead just hears the ToH (Tone on Hold). The remote worker and UC520 are both connected to the internet using Cisco 887 routers with a VPN established between the two 887's. The remote worker is using a 7941 handset. The UC520 is running a fairly old software pack (7.x) but has not shown any other problems so there hasnt previously been a need to upgrade.
Is it possible to get calls placed on hold by the remote worker to hear the external source MoH?
If so, is the problem to do with multicast packets across the VPN?
Is it possible to use unicast packets for the MoH using an external source? (I read that unicast disables the external port on the UC520)
Any assistance is appreciated