Replacing nusoap and curl using NTLM auth for sugar 12.0.3

Hi,

We are upgrading a customer from 11.x to sugar 13, but in 12.0.3 Nusoap has been removed. The customer is also using NTLM authentication for their soap connection. I am having troubles finding documentation covering this scenario. I have found that we should replace Nusoap with the sugarcrm \SoapClient, but no clear documentation found how to implement this soapclient and wether it is possible to get NTLM authentication to work.

Besides NuSoap, the customer also uses curl with NTLM authentication, which should also be replaced I asume. 

Any tips where to start?

Regards,

Stijn