I have posted the second article of my little series about the BPMN 2.0 Metamodel implementation for Eclipse.
http://www.sdn.sap.com/irj/scn/index?rid=/library/uuid/a0ec6d13-1ab4-2d10-dc87-c0a18d7f23c8
This part is highly technical and contains many in-depth tricks about EMF and what you can do it. You might find the article useful if you want to know how EMF reads and writes XML files and how you can use it to support standards like OMG BPMN 2.0 and others.