Mendix with servlets

Hei there. I am trying to integrate the paypal express payment within my application. There are other methods but am particularly interested in calling servlet code to execute the instructions. It seems like the best way to do it but am failing to use mendix with servlets. There particulary two two java files needed, and is a servlet file but am failing to integrate them. Any help will be highly appreciated.
1 answers

Did you figure out how to do it?