SSO across services/pools

I'm not totally sure what silverlight does from a protocol perspective, but I'm assuming it's not HTTP, but that it rides on HTTP for NTLM authentication. If that's true, then the next question is how you'd establish persistence between the HTTP ans silverlight services. So let's say the client talks to the HTTP service first, authenticates through APM, and establishes a session. If the same browser client is used to talk to silverlight, does it pass HTTP cookies?