How to add support of HTML help files (.chm) on Delphi XE2?

How to add support of HTML help files (.chm) on Delphi XE2? We need to use A-links (A-keywords) on HelpContext property of every control to lookup help pages. Delphi XE2 has native support of HTML help files by unit HTMLHelpViewer. But how to use it?

I suspect that to use A-links you need to do the following:

1. Assign an Application.OnHelp handler as described below.
2. Assign Application.HelpFile during program startup.
3. Call Application.HelpKeyword if you wish to invoke the help system with an A-link.
4. Set the HelpKeyword property for any GUI controls that you wish to respond to context sensitive F1 key presses.

The OnHelp handler looks like this:

function TMainForm.ApplicationHelp(Command: Word; 
  Data: THelpEventData; var CallHelp: Boolean): Boolean;
var
  Link: THH_AKLink;
  ALink: string;
begin
  CallHelp := False;
  Result := True;
  //argh, WinHelp commands
  case Command of
  HELP_COMMAND:
    begin
      ZeroMemory(@Link, SizeOf(Link));
      Link.cbStruct := SizeOf(Link);
      ALink := PChar(Data); // we are going to re-purpose the keyword as an A-link
      Link.pszKeywords := PChar(AnsiString(ALink)); // seems we have to pass a PAnsiChar ..
      Link.fIndexOnFail := True;
      HtmlHelp(GetDesktopWindow, Application.HelpFile, HH_ALINK_LOOKUP, 
        DWORD_PTR(@Link));
    end;
  end;
end;

The HtmlHelpViewer unit contains methods named LookupALink which do the same. But I don't see how they could ever be called.

The above approach is a little bit hacky because it interprets keywords as A-Links. If you want context sensitive help, I can't see what else you can do.