You can request this using:
editDate: [NULL TO 2012-09-17T15:00:00.846Z]
If you are interested in part of this, use:
editDate: [NULL TO 2012-09-17T15:00]
Note that you may need to avoid part of the request, for example:
editDate: [NULL TO 2012\-09\-17T15\:00]
, .
Raven Studio - β editDate .