I too have the the same question, I am running a Cisco Virtual Environment and I looking for ways to sniff traffic from a SharePoint Front end and the SQL back end running on the same physical virtual Blade? Cisco 1000V?
I do not believe it is possible, I at one point was testing a virtual ADM and unless someone was able to span traffic to the IP of the virtual appliance, it could not be done.
You can use the database activity monitoring software that McAfee has to monitor the database locally if spanning isn't an option, however I have never had the pleasure of attempting to use the database activity monitoring tool to send traffic to the DBM.
Hopefully it helps, and hopefully gives some direction on the topic.
enclosed resources will help you tap/mirror in an Virtual Environment: