ok, you can call me an idiot, in this case you are right
I was sure that media streaming was working some months ago, with an older gargoyle release, but I couldn't find out why it stopped working.
Now I've found the solution. I'm using mediatomb for media streaming. This program binds itself on the first interface ic can find during startup. if you have only one everything it's ok. But I started playing around with kvm based virtualization. In this way a new interface (a virtual bridge) was created. In the future, mediatomb was binding itself to this virtual bridge.
Result: no more streaming over the network!
I changed this bindung in mediatomb config to the "real" interface and now it works again.
So, please forget my crying about not working upnp streamin with gargoyle a wireless client bridge.
gargoyle works like a charm!
Thanks to all developers
best regards
Thomas