Tab with OnKeyDown and OnKeyUp

I have an empty form without any components on it. I use the OnKeyDown event to respond to keyboard events. It works for all keys I need it for but the Tab key.

I recently upgraded from BCB4 to BCB5. In BCB4 I used the following code, but it gives an error in BCB5. Anyways I couldn't catch the tab KeyUp with it, so how can I catch both those events in BCB5?

Thanks

//Code used in BCB4:

....
The .h
  void __fastcall KeyDown(Word &Key, Classes::TShiftState Shift);
  void __fastcall CMWantSpecialKey(TCMWantSpecialKey &Message);

  BEGIN_MESSAGE_MAP
     MESSAGE_HANDLER(CM_WANTSPECIALKEY , TCMWantSpecialKey, CMWantSpecialKey)
  END_MESSAGE_MAP(TForm)// Assumes this is in a form derived from TForm


The .cpp
void __fastcall TForm1::KeyDown(Word &Key, Classes::TShiftState Shift)
{
     if (Key == VK_TAB)
       // do something

  TForm::KeyDown(Key,Shift);
}
//-------------------------------------------------------
void __fastcall TForm1::CMWantSpecialKey(TCMWantSpecialKey &Message)
{
  if(Message.CharCode != VK_TAB)
     TForm::Dispatch((void*)&Message);
  else Message.Result = 1;
}
....