Re: Adding a Button
I'm not sure I understand the question.
But here is an idea. You can go into Admin>Catalog>Product Types and define a new product type specific for that product you want listed. You can fully customize the way you want. Including leaving off the add to cart. Then you can use the product description in Admin>Catalog>Categories/Products for that product and hard-code a "manual" button into the description.
Hope this is what you were looking for.
Lesli in SW Florida ~ writer, teacher, and dodging hurricanes!