Check a box…get a required text field

Hi!

I just want to know if Contact Form 7 can require a user to fill in a specific text field after clicking on a checkbox that goes with it. I’m working on a large order form with multiple products, each one with their own text field indicating “Quantity”. If the user forgets to add a number to the “Quantity” text field, the generated output will just show the selected product with no quantity next to it. This is very confusing to read when the output is generated and emailed.

I know how to make a checkbox a required field, and I also know how to make a text field a required field, but not how to connect the two. If this was a regular HTML/CSS form, I’d probably just be able to write something like this

However, since Contact Form 7 uses bracketed [shortcodes], I’m not sure how to proceed. Any help would be greatly appreciated. Thanks!

http://wordpress.org/extend/plugins/contact-form-7/