Receipt Template trying to Print Session Variable not working

Hello, I am setting mySession.Variable(1) in my add-in code that gets run right before the printing, I am using the Hook 1, which runs right before printing. So my hook is running fine and setting the variable, but I see no info or can not find any info on how to get my XML receipt template to print the variable. I tried the Session.Variable(1) in the receipt template, but I get a token error on the receipt template. What am I missing.

Thank you, Nick.