Messenger.Send(new RequestMessage<TEntity>) always returns System.InvalidOperationException

[maxplex]

Hi,
Really liking this Toolkit!

Messenger.Register<RequestMessage>(this, Receive); works with no apparent problem - the Messenger lists the relavent messages for the correct type of TEntity, but sending a requestmessage of type TEntity never results in any response other than InvalidOperation.

Am I getting something totally wrong here? Stuck, and need some feedback...

[maxplex]

Edit: Messenger.Register<RequestMessage<TEntity>>(this, Receive);...