Send By Channel ?

Hello,
I have several channels configured and I need the server to send a message to a specific client using a specific channel. So I'm using NetworkServer to send messages using the SendToAll and SendToClient methods:
http://docs.unity3d.com/ScriptReference/Networking.NetworkServer.html
But the API only offers SendByChannelToAll and SendByChannelToReady. There is no SendByChannelToClient. Is there a workaround for this ? The message is big and I can't afford...

Send By Channel ?