tableadapter will not return null values

I am trying to change the NullValue property of a field to return a null if the field is null.  Of course, this causes the followng error msg even though the underlying table allows null values:

"For columns not defined as System.String, the only valid value is (Throw exception)."

I see where others have had the same problem:

http://forums.microsoft.com/MSDN/ShowPost.aspx?PostID=436677&SiteID=1

http://forums.microsoft.com/MSDN/ShowPost.aspx?PostID=935074&SiteID=1

The preceeding threads are marked as "Answered" however the only answer I see is the acknowlgement of a bug.  Has this been fixed? Where is the documentation?

Thanks