Question : VirtualBox and multicast

We are running VirtualBox 3.1.8 on a Ubuntu host with Kubuntu guests. The guest's network connections are configured as bridged through virtualbox.
For some reason, we cannot get any multicast traffic to work to the guests or from the host to the guests.
Does anyone know of any issues with multicast working through virtualbox virtual or bridged connections?
Thank you for your help,

Answer : VirtualBox and multicast

I think we have found a successful "fix".
In the Linux virtual hosts network adapter properties, it is not enough to specify an IP, subnet mask and gateway. By manually configuring the network and broadcast addresses, we were able to realize full mulitcast functionality.