I'm trying to call a WSE 2.0 web service from a WSE 3.0 client. The
articles I've read say that this should work if you stick to using
features of ws-Security 1.0.

Every time I call the web service I get this exception:
Microsoft.Web.Services2.Security.SecurityFault: The signature or
decryption was invalid

Does anyone have any suggestions on how to restrict WSE 3.0 to only use
WS-Security 1.0 features?

Here is some sample code from the WSE 3.0 client:

UsernameToken token = new UsernameToken("username", "password");
MessageSignature signature = new MessageSignature(token);

service.RequestSoapContext.Security.Tokens.Add(token);
service.RequestSoapContext.Security.Elements.Add(signature);
service.RequestSoapContext.Security.Timestamp.TtlInSeconds = 60;

(The last 3 lines have obsolete warnings.)

I know the message is being signed. If I send the wrong password I get
an error of "The computed password digest doesn't match that of the
incoming username token."

Any pointers would be appreciated.

Thanks,
Don