Resolve the Pop-Up Issue

HI Everyone,

                     Hope everyone doing fine.I am facing one issue in the application(http protocol) .

Issue is:

               lLogin part is not designed like other web application.Here login window designed as OS-POPUP window.There i have to enter my username and password.Then it will login into the application.While recording the script using web(http/html) protocol.It is not capturing the login part (username,password as  i am entering through os pop window)
I  am getting (401 error) during reply.I tired using web_set_user function as well.Still i am getting the same error.
I have tried with different option as well like (socket level,winlnet level) nothing is working.Please provide some idea how to resolve this issue.Thanks everyone :)