Yes, probably Windows mobile themes would be best. But the longer I think about it, the less probable it seems to me that this is possible. The start button is no link, but a menu-button in a application (the windows shell). So there will most probably no way to link to it, because you would have to link to a function in a program, not to a program. So good luck with this one . Why do you want to have it btw?
And if i search to a program which has this function? Or any mortscript?
I'm looking for it because i like more wm start menu than spb one... Then i also modified start menu with my personal icons...