Using the Null function to delete an attribute from a user in the metaverse

RC1 Update 3 adds a new Null function, which (to me) sounds like it should flow a null value into the destination attribute.  I have a case where i am flowing a date from SQL into the metaverse.  Just for testing, I tried a basic flow of:

Null()->employeeEndDate

This seems to function the same as this:

""-employeeEndDate

Both will add the employeeEndDate attribute to the metaverse object with a blank (not null) value.  To me, Null() seems like it should be equivalent of mventry("employeeEndDate").Delete, but it doesn't seem to.  Ultimately, what I want is to flow the value in if it is present in my connector space, and delete it if it is not.  Something like this:

IIF(IsPresent(TermDate),DateTimeFormat(TermDate,"yyyy-MM-ddTHH:mm:ss.000"),Null())


Anyone have any thouse on this?  Is there an easier to way to do this that I am overlooking?

Thanks,
Keith