Little documented is the date format of the EmployeeStartDate and the EmployeeEndDate in Forefront Identity Manager 2010.
If you look into the date format of the attributes of a user in the portal it self, it'll tell you that the format is M/d/yyyy hh:mm tt. Feeding the FIM MA this format will make it "sick".
The correct format would be to se the builtin function DateTimeFormat in the Inbound Synchronization Rule and use the function DateTimeFormat, so that the end result would be:
Here is a screenshot with an Inbound Flow Rule from a live installation doing just that (or close to, as I want a specific time stamp to go into the portal, but you should get the idea) -
This will convert a SQL DateTime attribute (HireDate) to the format the FIM portal wants it in.