APM Enable only NTLM

Dear, i want to configure a external site exposed by apm.

 

I need that if the user is not internal of the domain (than NTLM fail) the APM policy will not prompt the basic authentication but balance it to a default pool.

 

Is it possibile to configure it? I've already tried, but if the NTLM fail it will show a pop-up. If i ignore the pop-up the authentication will fail and the policy doesn't go to fallback.

 

Thanks in advace guys. Bye