This functionality is supported only if you are using the Classic Agent.
The two built-in constants, sUserName and sPassword, are enclosed in comment tags in the generated test frame. You can un-comment those constants and supply values to specify your user name and password, if your application requires you to enter such information. Once you have done this, whenever you are loading a page, and you are prompted for user name and password, Silk Test Classic will automatically supply the values and click OK in the message box. The test case can run unattended.