Silverlight Network Connection priority and bandwidth

Question

Is there any way to set QoS value for socket in Silverlight?

I'd like to open a second connection on a background thread to send some large amount of a data, but with a lower possible network priority. Just without eating the bandwidth of other (let's say "realtime") connections.

I meant something like this:
http://msdn.microsoft.com/en-us/library/8a3744sh.aspx
http://msdn.microsoft.com/en-us/library/system.net.sockets.iocontrolcode.aspx