RFC related Web Service doesn't seem to update

Situation:

You are exposing a RFC through Biztalk as a Web Service.
An update was made on the RFC and on development environment, and works well. When passing to test/production environment still refers to the old version.

Solution:

You can even delete the application, it has nothing to do with that DLL. The problem is that for applications related to RFC, Biztalk generates another DLL, refering only to the RFC schema. Supposing that all RFC's are SAP-made and unchangeable, those DLL's are not updated when you reinstall your app.

The only way to avoid that problem is:

Delete that DLL at a folder similar to C:\Program Files\Microsoft BizTalk Adapter v2.0 for mySAP Business Suite\Bin

Install your app MSI

Restart application, Host Instance and local IIS

Thanks to http://timrayburn.net/blog/learning-adapters-sap/

Registering adapters while publishing services

The Messaging Engine failed to register the adapter for "WCF-BasicHttp" for the receive location "*/*.svc". Please verify that the receive location exists, and that the isolated adapter runs under an account that has access to the BizTalk databases.

This time the problem is not on BizTalk but on IIS. The Application Pool for this website must be running not under a predefined service, but on an account with permissions over Biztalk.

Solution:

Create a new Application Pool for Biztalk, and on the Identity Tab select Configurable and insert the login. Associate the Web Site to this new app and refresh the svc page.