I had a similar issue where I was bookmarking a URL and then the webpage was calling for an internal URL. It was for a bank and they were hosting the check images on another internal server. So when the repoffice teller clicked on the link for the check image it called a URL by IP (they should have used names instead )
How I fixed the problem:
On the Bookmark make sure you enable smart tunnel
All connections the URL calls will use the tunnel. You may have to play with where you call the URL from either from the bookmark itself or from an internal landing page.
Hope this helps