While we don't generate procedures with dynamic parameters in Designer 8.5, we will in 8.6. See How to Consume a JSON REST Web Service in Teiid Designer
That doesn't mean you can't do it in 8.5, it is just a manual process to create the procedure. You can follow the example in the article to manually add the dynamic parameters to your procedure OR you can update from master to get the new functionality: http://download.jboss.org/jbosstools/builds/staging/jbosstools-teiid-designer_trunk/all/repo/
Thank you for your reply! I just forgot to add a semicolon somewhere.