Thax for posting your question to our blog site.
Intel's SR-IOV solution does provide multcast support for VF's. It is done via a hash on the least significant bits of the multicast address by default. This is something you can change and recompile the driver, however there is no user tool available to do this dynamically.
Can you do a register dump using ethregs (Intel Ethernet Drivers and Utilities - Browse /Ethregs - Register Dump Tool at SourceForge.net) and provide it to me - we will take a look at how things are configured.
thanx,
Patrick