Create a button for a specific listing
Using the Custom Buttons extension you can create a custom button to use on a specific listing.
Add a new button
Goto the Custom Buttons extension settings page and increase the number of buttons and press save. Open the new button tab and configure the settings as shown below.
You can link to an external location or a page on your own website.
In the Custom Field Name field enter in property_unique_id which relates to the Unique ID on your edit listing page.
Your button will now appear on a specific listing.