Как отключать стили XP для отдельных контролов?

Темы должны быть включены и манифест лежать на форме:

unit Unit1;

interface

uses
  Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,
  Dialogs, ExtCtrls, StdCtrls, ComCtrls, XPMan;

type
  TForm1 = class(TForm)
    Button1: TButton;
    Button2: TButton;
    Button3: TButton;
    Button4: TButton;
    Button5: TButton;
    XPManifest1: TXPManifest;
    procedure FormCreate(Sender: TObject);
  private
    procedure Unload2Themes(var M:TMSG); message WM_USER+1;
  public
    { Public declarations }
  end;

var
  Form1: TForm1;

implementation

{$R *.dfm}

function SetWindowTheme(hwnd: HWND; pszSubAppName: LPCWSTR; 
                        pszSubIdList: LPCWSTR): HRESULT; stdcall;  external 'uxtheme.dll';

procedure TForm1.Unload2Themes(var M: TMSG);
begin
  SetWindowTheme(Button4.Handle, ' ', ' ');
  SetWindowTheme(Button5.Handle, ' ', ' ');
  SetWindowTheme(Form1.Handle, ' ', ' ');
end;

procedure TForm1.FormCreate(Sender: TObject);
begin
 PostMessage(Handle,WM_USER+1,0,0)
end;

end.