Storyline 2 Quiz customization

Hi,

Overview:

I am working on a course  with 3 Scenarios and with in each Scenario there are 5 questions.  Once you finish a Scenario you are prompted back to the main page from where you can select the next Scenario. Of course you can revisit a Scenario and view your selected answers.   

Right now the default selection option for a multiple Response question is a check mark (e.g. when you click to select an answer, the selection box displays a check mark). 

Problem:

a From a UX point of view I find the check mark confusing. If the user re-visits a quiz question, the user sees the previously selected check marks and  assumes that those are the correct answers. When in fact a the check mark only indicates selection not "correct" or "incorrect" . 

Question:

How can I change the check mark to a different icon ( e.g. a dot) ?

I know I can go to the edit setting and put a dot shape on top of the check mark but professional .