Matt,
There's an option in your bank setup (From AP: Edit > Banks) to "bypass additional forms". I bet you've got this enabled.
Turn this off for your EFT bank, and you'll be prompted to print the additional form.
You can then go into the spec designer (Maintenance > Maintain Specifications) and open up the spec file called "Additional Form". That will give you a decent starting point.
Spec design can be tricky the first few times. Your Adagio consultant can help with this.