The Article below is from Maemo Briefs regarding Media Sharing:
As you know, due to the aim of getting the N9 DLNA-certified, developers had to introduce some restrictions.
One of the most annoying limitation from an end user point of view is that you can’t share arbitrary videos or music which you may have put on your device.
Another, though minor, issue is that it’s not possible to change the name shown in UPnP or DLNA clients on the network.
Source Maemo Briefs