Using OrientDB as EMF persistent layer

I’m interested in using orientdb as a storage layer for EMF (Eclipse Modeling Framework).

I found an old article about it: http://people.disim.univaq.it/diruscio/sites/XM2012/xm2012_submission_5.pdf.

I also have a small prototype to solve this problem. Example code can be found here:
Java tests


Test model

Anyone interested in storing EMF models in orientdb?

Some solutions are not obvious and I would like to discuss them.
In particular, whether to use ODocument for storing entities, or OVertex, how to model CrossReferences, etc.