Call WebService from PL/SQL - portType name error

Hello,

I would like to call a web service from the scitegic server by PL/SQL procedure (oracle).
In the WSDL xml, i get the targetNamespace (http://scitegic.com/soap/service), the service name (WebServiceDemo),
the wsdl URL (http://my_url/WebServiceDemo?WSDL),the portType name (WebServiceDemoPortType), the operation name (Login).

When i call the web service, i get an error about the port :
"...service: {http://scitegic.com/soap/service}WebServiceDemo does not contain port:..."

However, when i call a public web service (http://www.dataaccess.com/webservicesserver/numberconversion.wso?WSDL), it works fine.

If necessary, i can post the PL/SQL code.

Any help is appreciated.

Version 7.0.1

Thanks
Grégory