If This Option Then Attach A File

I have a product that, if a certain option is chosen, the purchaser can upload a file. I can't seem to find a way to get this to work with the defaults in CS-Cart. Anyone have any tips?

Update

I have a product that, if a certain option is chosen, the purchaser can upload a file. I can't seem to find a way to get this to work with the defaults in CS-Cart. Anyone have any tips?

I found option_types.tpl and added in my own option, however it still doesn't show up on the list, is there a complete list of files that need to be changed?

I am afraid, quite complex code changes are required to do it. There is no easy way to do it