Revision support

Dear list,

First of all, a huge thank you for providing this module. It is absolute great and of immense usefulness.

One thing I am running across is support for revisions. I see that Drupal 7 entities can support revisions and am wondering what is needed to get revision support for the entity types that one can create with this model.

Any high- or low-level guidelines would be very much appreciated!

Thanks,
Kaspar