NetTcpBinding with Streaming and Session

I’m trying to set up a WcfService with the use of NetTcpBinding. I use Transfer mode Streamed since I will transfer large files. I need to use Session, and I have read that NetTcpBinding supports this, but when I turn it on like:

SessionMode=SessionMode.Required
I get the error:

System.InvalidOperationException: Contract requires Session, but Binding 'NetTcpBinding' doesn't support it or isn't configured properly to support it.

Does anyone know what I have to do to make NetTcpBinding work with sessions? Thanks for any help