WCF/WF - Windows Authentication for WCF service in IIS7

Hi, I have hosted WCF service on IIS7 using BizTalk WCF publishing Wizard and for that service I have enabled Windows Authentication, my requirement is whenever I browse the service it should ask me for credentials, how can i configure this, I though when i enable Windows Auth it will ask me for teh credentials whenever I browse teh service but its not asking m efor credentials now, what should I configure in the service to pop up credentials window when I browse this service, Any Ideas?

Thanks in Advance

Did you uncheck "Anonymous" in IIS?

Yes I did, I have unchecked or Disabled Anonymous access and enabled only Windows Auth., do I have to change some where? like Web.Config, WcfServiceDescription.xml, binding file.xml.

do you have

<system.web>
  ...
  <authentication mode="Windows"/>
  ...
</system.web>

in your web.config?

Yes I do have that in my Web.Config.

Any update in this issue? How did you fix this? Can you please post back the solution/idea you have, I have the same issue. Thanks and appreciate your help. Jas