I don't know what wsdl's you were dealing with, but I met a fair amount of them who were not consumable by neither php-soap, python and even a java client while trying to read a .net one.

The reason people are writing their own envelopes in cases (like I did also) is because the tooling is not delivering up to it's promises. (Let alone that the server might not even understand the two-line-code genertated nusoap reponse because he interpretes some ws-* rules about namespaces differently.

The conclusion is: nobody wants to write his/her own envelopes.