how to customize the booking form on Events+

Is there a way I can add more fields to the booking form on the events+ plugin?

Right now, my form has NAME, PHONE, EMAIL, and COMMENT. I want to add more fields. Specifically radio button for YES/NO.

Here's the link to the page i'm referring to: http://atsafetytraining.ca/events/ossa-fall-protection-2013-06-07/