[Plugin: WP Survey And Quiz Tool] How to customize PDF Certificate from DocRaptor

I am trying to customize the certificate with a background image via html and css. I understand it says it’s capable but I have no idea where to have the html converted to PDF. I do know that if not using a PDF template, then it will read what’s in the file “pdf.php” around line 50. I also want javascript to be ran before it’s converted to PDF. I found the answer on DocRaptor but don’t know where to implement it. Trust me guys, I have done my research as well. Haven’t found a solution.

Thanks for your support in advance!

http://wordpress.org/extend/plugins/wp-survey-and-quiz-tool/