text variables in Storyline

Hi 

I am using text variables to create user interactions which get the user to enter text which is then compared against a "model answer".

When I preview the lessons in storyline, I am able to backspace and delete to change answers and correct spelling errors.

However when I publish the lesson this is no longer possible.

To  quote from Omar Kyam  "The moving hand once having writ moves on. Nor all thy piety nor wit can lure it back to cancel half a line."

Any help in solving this would be greatly appreciated 

thanks 

Cameron