At first sight you think: no problem... but as the article says
Here the deployment fails with an error that it is unable to validate the WSDL for the Partner Link. The issue here is that as part of the deployment process we are “over-writing” the old stub version of the process, with a new version.
I think for business processes you should not use recursive BPEL, but it's like working with EXCEL. After the first macros you start developing a flight simulator ;-)