This solution is for those who use also GMF. In one of your plug-ins (or create a new empty plug-in for that) add following section to plugin.xml:


<extension point="org.eclipse.emf.ecore.extension_parser">
   <parser type="MY_SEMANTIC_MODEL_FILE_EXTENSION"
      class="org.eclipse.gmf.runtime.emf.core.resources.GMFResourceFactory">
   </parser>
</extension>

It will make EMF use GMFResourceFactory for XMI [de]serialization. GMFResourceFactory enables usage of UUIDs. Don’t forget to replace MY_SEMANTIC_MODEL_FILE_EXTENSION with your own file extension.