I am using WSE3 with usernametoken authentication and for some reason on the
server a call to
RequestSoapContext.Current.Credentials.UltimateReceiver.GetClientToken<UsernameToken>() returns null.

Now, I know the username token is being sent by the client and received by
the web service for 2 reasons:
1) If the username token is created using an invalid username/password
combo, then I get a SecurityFault exception.
2) I have turned on diagnostics at both ends and inspected the soap messages
and the username token is in there ok.

I reckon I must be doing something really silly, but I can't think of
anything. As I say, I *know* the username token is being received by the web
service (so my configuration files must be set up correctly, right?) and yet
the call to get the token returns null and I just can't figure it out.

I am not using certifcates or any other form of authenticating/encryption,
just the usernameOverTransportSecurity turnkey (with default
UsernameTokenManager, as I'm authenticating against AD, and like I say it
authenticates successfully). I have other web services where everything works
fine, and I'm scratching my head as I can't see how they're any different.

Any help/ideas would be greatly appreciated.

Thanks

Mark