You can embed a participant center in a PageBuilder page which will then allow you to set the wrapper for the Page.
  1. Create a secure Pagebuilder page.
  2. Add [[S409]] to the HTML content of the page.
  3. Set the Page Wrapper for the newly created page.
Now the Participant center will use the wrapper set on the newly created page.

Once completed you will need to update the Teamraiser to utilize the new participant center.