Delphi OTA interface - AddPluginBitmap function does not display the caption

When I use the following code in my package (a Delphi OTA/IDE plugin):

unit uSplashRegister;

interface

implementation

{$R SPLASHREGISTER.RES}

uses
  Classes, Windows, Graphics, ToolsAPI,DesignIntf;

ResourceString
  strSplashScreenName = 'MyTestCaption';

procedure AddSplashText;
var
  bmp: HBITMAP;
begin
  bmp := LoadBitmap(FindResourceHInstance(HInstance), 'LOGO');
  if assigned(SplashScreenServices) then
  begin
    Splas开发者_开发百科hScreenServices.AddPluginBitmap(strSplashScreenName,bmp,false,'Registered');
  end;
end;


initialization
   AddSplashText;
end.

I see the text "MyTestCaption" in Delphi XE and in Delphi 2009. In Delphi 2007 however, the caption is not visible. The word "Registered" is visible, the logo also.

Anyone an idea why I don't see the caption?