Not sure but you can try something like the below 2 examples (replace the appropriate values of course):

lcuser = ""          && replace with your username
lcpassword = ""      && replace with your password
lcsite = ""          && replacw with the url

*-------------- Test Example 1
loWScript = CreateObject("WScript.Shell") 
ln=loWScript.RegRead('HKCU\Software\Microsoft\Windows\CurrentVersion\Internet Settings\ProxyEnable') 
loservice = CREATEOBJECT('mssoap.soapclient30')
loservice.mssoapinit("http://www.levelextreme.com/WebService/universalthread.asmx?WSDL") && change to lcsite
IF ln = 1
   loService.ConnectorProperty.UseProxy = .t.
ENDIF
loservice.ConnectorProperty("AuthUser") = lcuser 
loservice.ConnectorProperty("AuthPassword") = lcpassword
loservice.ConnectorProperty("WinHTTPAuthScheme") = 1
lcXML=loservice.GetMessage(DATE(),5)
RELEASE loservice

*--------------Test Example 2
loUniversalThread=Createobject("mssoap.soapclient30")
loUniversalThread.mssoapinit("http://www.levelextreme.com/WebService/universalthread.asmx?WSDL") && change to lcsite
loUniversalThread.Login(lcuser,lcPassword)
lcXML=loUniversalThread.GetMessage(DATE(),5)
RELEASE loUnivesalThread
RETURN