First, there are a number of servers that do support menus. The Netgear EVA 8000 and a few others do. Second, someone who works for the developers of the software that DLink uses was on the AVS forum and has stated that they were working on this feature for a future release. That statement has to be 6 months old now though. Furthermore, given the extremely slow release of firmware and software updates from DLink, my guess is that it won't come out before next year and may not support the DSM-520.
Alan