SaveOption EntityTypesExcludedFromPostSaveRefetch does no work as expected

I have a table with a primary key of type char(7) (CharPK), a timestamp field (ts) and a date field (LastUpdated) which is automatically updated to getdate() by a table trigger. The timestamp field is defined with concurrency strategy "Client" in the EF model.
I define AfterGet interceptors for all string-fields (including the primary key field) in the table to trim the trailing spaces of char-fields and to guarantee that optional string fields do not return Nothing:

 <AfterGet(EntityPropertyNames.(CharPK), AfterGet(EntityPropertyNames.OtherCharFields)>
  Public Function TrimMultipleProps(ByVal strPropValue As String) As String
    If Not String.IsNullOrEmpty(strPropValue) Then
      If strPropValue.EndsWith(" ") Then
        Return strPropValue.TrimEnd()
      Else
        Return strPropValue
      End If
    Else
      'Guarantee to not return Nothing
      Return String.Empty
    End If
  End Function

When I do this I cannot save new entities with PKs shorter than seven characters because the PK is trimmed and when DevForce reads the record after saving it detects a difference and throws an exception.
Therefore I suppress reading after save:

Dim so As New SaveOptions()
so.EntityTypesExcludedFromPostSaveRefetch = New List(Of Type) From {GetType(EntityWithCharPK)}
_mgr.DefaultSaveOptions = so

In this situation mgr.SaveChanges submits SQL like this:

exec sp_executesql N'update [dbo].[TableWithCharPK]
set [SomeColumn] = @0
where (([CharPK] = @1) and ([ts] = @2))
select [LastUpdated], [Created], [ts], [ComputedColumn1], [ComputedColumn2]
from [dbo].[TableWithCharPK]
where @@ROWCOUNT > 0 and [CharPK] = @1',N'@0 varchar(25),@1 char(7),@2 binary(8)',@0='f',@1='1234   ',@2=0x000000000011D6EA

At first I was impressed because exactly the necessary columns are read after the update.
The problem is, that none of the values in the select list are actually read into the entity.
The timestamp value in the entity stays unchanged after a save operation.
When I try to save this entity a second time, DevForce throws an error because it detects a concurrency problem because of the outdated timestamp value.

Is this a bug or am I'm missing something?

Thanks

Herbert

Thanks for the reply. But it still leaves the question why something is read in after the update when it is not used. That's a waste of resources.

My original problem was how I can achive that a Property of a char primary key is automatically trimmed. Example: The customer ID stored in the database is 'ABCD   ' (char(7). The value of the Property Customer.ID should provide 'ABCD'. Do you know a solution for this?

Thanks Herbert

Please, read my thread. Property interceptors were my first try. But they didn't work with a primary key of type char.

>>DevForce does a Refresh on the underlying EF ObjectContext after the save.  It's EF, via the Refresh, which determines the query to issue.  The query will include any property marked as "store-generated", along with concurrency columns.

If DevForce does a refresh, why doesn't it really refresh the object, after it has queried the new values?

Thanks Herbert