How to change RETURN keystroke to TAB keystroke

Hi!

With most controls I can substitute RETURN with TAB when I do this in
Form.IsShortCut event:

if (Message.CharCode = VK_RETURN) then
begin
     Message.CharCode := VK_TAB;
end;

But this doesn't work when TDBGrid's inplace editor is focused. Probably
editor gets the keystroke before IsShortCut. How can I tweak the keystroke
BEFORE it's presented to TDBGrid's inplace editor?

thank you!

Aivar