I'm working on aC# client that needs to send unsigned messages to a server that will send back a signed message. There aren't any standard policies that conform to this, and when I tried creating a custom policy assertion, the ValidateMessageSecurity function for the ReceiveSecurityFilter does not get called. Can anyone point me in the right direction. Thanks.

The only thing I know about WSE is that WCF should be used instead for new development, wherever possible.