dynamic crit in template

I'm creating a macro using the dmg template and want to allow the user to select whether the damage should roll as crit.  I see the template allows me to set {{crit=1}} to indicate roll crit damage, but I'm unable to figure out how to combine this with a drop down (or other user input).  Trying ... {{ ?{Crit?|Yes,crit=1|No,crit=0} }}  but it seems to get ignored.  Any thoughts would be appreciated.

The {{crit}} is just a toggle as to whether the crit damage will display or not, and if there's anything after the = then it will display.  You don't want a '1'/'0', you want a '1'/' ' (blank value).  I just tested with this and it worked: &{template:dmg} {{rname=Test DMG}} {{damage=1}} {{dmg1flag=1}} {{dmg1=[[1d6]]}} {{dmg1type=Slashing}} {{?{Crit?|Yes,crit=1|No,crit= }}} {{crit1=[[1d6]]}} {{charname=Test Name}}