I've never done a RETURN from a SP. Is that just read back into the Data Reader in .NET? Here is the code I use, and I base my results on if there were records affected or not.

        Try
            Conn1.Open()
            DataReader = DeleteCommand.ExecuteReader(CommandBehavior.SingleRow)
        Catch
            Conn1.Close()
            DeleteCommand.Dispose()
            Return -1
        Finally
            Conn1.Close()
            DeleteCommand.Dispose()
        End Try
        If DataReader.RecordsAffected > 0 Then
            Return 1
        Else
            Return 0
        End If