Currently data joined to FDO soources is available for query and styling, but not for editing. It requires me to select an object, then go find it again in the source table - it's pretty awkward. Having the ability to edit the source data from the joined data view would really enhance the ability for Map to manage connected datasets and reduce the need for other programs.
I've been hoping for data editing tools for years now. Unfortunately, I'm not aware of any solutions. I'm still using link templates to connect with SQL databases and, in the year 2012, copy and paste information into all the fields. I understand you're attempting to manipulate data through FDO's which, seems to be even less useful for data entry based on your post. Have you had any luck finding a good work around?