Howto add new plugin dependencies to internal maven repository
* create directory "newplugins"
* copy plugins jar from existing Eclipse (Juno 3.8) installation to "newplugins" directory (example: org.eclipse.core.databinding.beans_1.2.200.v20120523-1955.jar)
* run the "deploy_new_plugins.sh" script
* delete the "newplugins" directory
* add the new dependency (including version) to the parent pom.xml "dependencyManagement" section
* add the new dependency (excluding version) to the repository/pom.xml 
* now you can add the new dependency (excluding version) to the plugin's pom.xml
* run "mvn install" from the project root to see if all works

The script splits the original filename (e.g. org.eclipse.core.databinding.beans_1.2.200.v20120523-1955.jar) and extracts groupId, artifactId, version, and packaging.