Add vApp to Catalog - Customize VM settings

I've been able to figure out how to add a vApp as a template into a catalog, but when I do, it defaults to "Make identical copy." I'd like to set it as "Customize VM settings," but when I tried to update the vApp template's customization section to do so, I got an error saying "Cannot change value between 'Make Identical Copy' and 'Customize VM Settings' (for CustomizeOnInstantiate)."

Any ideas on how else I can try this?