[David Iglesias]

I think that the popup shows up everytime you start the game with parameters so you don't need to make an application to show it up, you can just trigger it by creating a shortcut to the game and adding the params at the end of the path.

In any case, that popup is something that Steam adds for security, so I don't think you can bypass it unless you're thinking is some kind of script that clicks the OK button for you.