CBuilder 5 messages and custom components

Hi i need to access the CM_MOUSEENTER and CM_MOUSELEAVE messages in this cusomised button.

The idea is to change the glyph of the button as you move your mouse ovvr the button.

This is some of the basic code so far but it doesn't work. It is suppose to change the caption of the button it self.

Can anybody help ?
===========================================
.h file:
===========================================
//---------------------------------------------------------------------------

#ifndef UltBitBtnH
#define UltBitBtnH
//---------------------------------------------------------------------------
#include <SysUtils.hpp>
#include <Controls.hpp>
#include <Classes.hpp>
#include <Forms.hpp>
#include <Buttons.hpp>
#include <StdCtrls.hpp>
//---------------------------------------------------------------------------
class PACKAGE TUltBitBtn : public TBitBtn
{
private:
   Graphics::TBitmap* FOffGlyph;
   Graphics::TBitmap* FOnGlyph;
      MESSAGE void __fastcall CMMouseEnter(Messages::TWMMouse &Message);
      MESSAGE void __fastcall CMMouseLeave(Messages::TWMMouse &Message);
   BEGIN_MESSAGE_MAP
      MESSAGE_HANDLER(CM_MOUSEENTER, TWMMouse, CMMouseEnter)
      MESSAGE_HANDLER(CM_MOUSELEAVE, TWMMouse, CMMouseLeave)
   END_MESSAGE_MAP(TControl)

protected:
public:
   __fastcall TUltBitBtn(TComponent* Owner);
   __fastcall ~TUltBitBtn();
__published:
};
//---------------------------------------------------------------------------
#endif

===========================================
.cpp file:
===========================================
//---------------------------------------------------------------------------

#include <vcl.h>
#pragma hdrstop

#include "UltBitBtn.h"
#pragma package(smart_init)
//---------------------------------------------------------------------------
// ValidCtrCheck is used to assure that the components created do not have
// any pure virtual functions.
//

static inline void ValidCtrCheck(TUltBitBtn *)
{
   new TUltBitBtn(NULL);
}
//---------------------------------------------------------------------------
__fastcall TUltBitBtn::TUltBitBtn(TComponent* Owner)
   : TBitBtn(Owner)
{
   FOffGlyph = new Graphics::TBitmap();
   FOnGlyph = new Graphics::TBitmap();
}

//---------------------------------------------------------------------------
__fastcall TUltBitBtn::~TUltBitBtn()
{
   delete FOffGlyph;
   delete FOnGlyph;
}

//---------------------------------------------------------------------------
namespace Ultbitbtn
{
   void __fastcall PACKAGE Register()
   {
      TComponentClass classes[1] = {__classid(TUltBitBtn)};
      RegisterComponents("Own", classes, 0);
   }
}
//---------------------------------------------------------------------------
// Message handlers
MESSAGE void __fastcall TUltBitBtn::CMMouseEnter(Messages::TWMMouse &Message)
{
   Caption = "Enter";
   Invalidate();
}

MESSAGE void __fastcall TUltBitBtn::CMMouseLeave(Messages::TWMMouse &Message)
{
   Caption = "Leave";
   Invalidate();
}

//---------------------------------------------------------------------------