WSUS API 3.0 without Active directory Trust Relationsip

I want to use the WSUS API, I can access this api if there is Active directory trust relationship. but I cannot use this api without that. Provide method and demo how to use without AD and with credentials

This is the method:
IUpdateServer server = AdminProxy.GetUpdateServer("MyWsusServer", true, 443);

This method is highlighted in this API
https://docs.microsoft.com/en-us/previous-versions/windows/desktop/ms744593(v=vs.85)