Hi Max,
Currently adding support for Date property is not on our list - I don't think we even have a work item for this. Having said that we are always interested in contributions that improve Entity Framework. I would recommend writing a short proposal on how this would be done and we would take it from there. Note that to contribute the actual code you need to sign the CLA. You can find more details about contributing here:http://entityframework.codeplex.com/wikipage?title=Contributing
Thanks,
Pawel