The simplest thing to do would be to make your link on your hosted webpage a link to a dynamic dns page. eg mattserver.dyndns.org and let the dyndns script in your e-smith box do the rest.
If you use this service, RENAME your esmith box "mattserver.dyndns.org" for the script to work properly and auto update, OR search for "dyndns" in these forums to find the exact script to edit to make it work properly.
You'll have to virtual host the mattserver.dyndns.org in either case.