OpenSTA

The script generated by the Modeler when the session
requires a login/password cannot be replayed
successfully.

The Server first challenges for a "Basic" authentification,
then it turns this auth. into a NTLM auth.

The generated script includes statements such as:

BUILD AUTHENTICATION BLOB &
FOR BASIC &
FROM USER "admin" PASSWORD "" DOMAIN ""
&
INTO blob_2_1

and further:

Load Response_Info Header on 3 &
Into blob_3_0 &
,WITH "WWW-Authenticate"

BUILD AUTHENTICATION BLOB &
FOR NTLM &
FROM BLOB blob_3_0 &
INTO blob_3_0

But requests are all denied by the Web server.
IIS server just require a valid user for itself, it does not
belong to a Windows Domain.