Relationship help!!!!!!!!!!!

I have two files, one where invoice information is enter and another where I format that info for the email to send to the customers, now in both fields I have a field called con it's global and set to auto enter on creation now what happens is when I create an invoice, in the invoice file the con field auto updates and it's suppose to autoupdate in the email file as well but it doesn't I have to manually enter in the con field the corresponding number then the data shows up correctly, how do I arrange or script this so that I don't have to manually enter the number, I'm going to try to attatch a screenshot of the code I'm using for my email button in the invoice file, it's referencing a script in the email file, and the reason I'm doing my db this way is b/c the email file has a custom function that I need and I don't have DEV 7