Rebroadcast servers should be able to take a compressed VRS feed and rebroadcast it in BaseStation format. You can convert anything to BaseStation format. The only conversions that VRS places restrictions on in a rebroadcast server are where you are converting from a cooked format back to a raw format, e.g. the receiver is Compressed VRS and you want to rebroadcast as AVR.
Are you having trouble getting Virtual Radar Server installed and running? If so then this is the place to ask about it.