Escape summons the main menu, so pad_start=menu_main should give you the same thing.
Except you can't close the menu with that same key. Unfortunately, keybinds aren't processed while the menu is open; otherwise I'd have given you a pair of aliases that would cause the key to rebind itself back and forth between menu_main and closemenu...
So, I have the same problem. Controller up and down works fine but no button on my pad acts as ENTER. So basically I would like to start the game without a keyboard. I cannot find anyway to do this. YOu had any luck?