Web service support has been greatly improved in version 2.4 of our technology. You can expose functionality of your application by publishing a microflow as a web service. The necessary code (WSDL) is automatically generated and can be used by external systems (Mendix or otherwise).
Importing web services is also much easier now. After importing a WSDL description into the Modeler you can start calling the web services described therein from your microflows. The results of those web services can be mapped using the earlier described visual XML mapping functionality.
All the low-level fiddling with different styles of WSDL and conversion of values is handled under the hood. The promise of web services finally comes true!