We have an example Driver installation script on wiki at: https://www.jboss.org/community/docs/DOC-13271
Near the bottom are the steps needed to import the jars into the common connector/extension jar location via the UDFs view.
This feature was added in our most recent MetaMatrix release prior to open sourcing the project. We've got a little UI work to do yet to simplify this process, so feedback is welcome.
Teiid Designer Project Lead