Here are the steps that will allow you to set your desired page wrapper to those links:
  1. Go to the email message desired to adjust
  2. Click "Edit"
  3. Go to Step 4. HTML Content
  4. Locate the "Unsubscribe" or "View Message as a Webpage" text
  5. Place your cursor within that text or highlight it.
  6. Click the chain icon from the toolbar or right click to Insert/Edit
  7. Click browse convio links
  8. Select Link Type "Email"
  9. Click "Unsubscribe" or "Message Viewer"
  10. When new window appears, scroll down to "Page Wrapper" and select the desired Page Wrapper (all appear here regardless of Security Category)
  11. Click "Select"
  12. Click "Update"
  13. Save
  14. Go to Next step: "Plain Text Content" and click "Convert to Plain Text"
  15. Follow through with approving the message.

Result:
Now, when you set up and send the delivery and those links are clicked it will adhere to the Page Wrapper that you defined through these steps.