Need help with openDialog

In the Photoshop script I'm writing, I ask the user to open a file using:

     open(File(openDialog()));

That works fine. But the user will always be opening an Illustrator (.ai) file.

Normally that brings up a dialog box called "Import PDF".

But that dialog doesn't come up with this open command and just uses the default options. I need to set 2 values: 1) uncheck Anti-aliased, and 2) Mode to CMYK.

I'm new to this and I can't figure out how to set those options. (I don't understand Adobe's Javascript documentation.) Can someone help?

Thanks!