template layout override for virteumart

We've purchased an extension to allow users to enter various quantities for their item, such as 2.5 yds. The extension is added as a custom field to a product. Currently, the extension pricing and the product pricing are both showing on the detail page. See attached image. We need to remove the product pricing so only the extensions pricing is showing. These are the instructions from the company we purchased the extension from: You need a layout overwrite. You can choose different layouts per category/per product. so just create another layout, copy it to the overwrite folder and choose this layout for the products with the customplugin. [login to view URL] I need someone who can do this layout overwrite and let me know how to choose it for those products. Please note, this extension is not applied to ALL products, only to certain products.