SOAP web services XML

Hello

I'm having issues getting data from a SOAP WS XML. The source uses Preemptive basic HTTP authentication with user/pass which I've already received.

let
    Source = Xml.Tables(Web.Contents("URL"))
in
    Source

This returns attribute names and such but no data at all. I'm not prompted for authentication by the way.

I've tried to manipulate the headers 

let
    Source = Web.Contents("https://soap.fiskistofa.is/landing/v1/LandingService?wsdl", 
             [Headers=[Authorization="user pass"]]),
    Xml =  Xml.Tables(Source)
in
    Xml

This is the form https://soap.fiskistofa.is/landing/v1/LandingService?xsd=1

Does anyone have any idea how to actually get data from this ?