[support] Custom error messages for access denied pages

I want to set the title and error message to a custom message for a few specific pages on my site. I have the logontoboggan module installed and was thinking of modifying that, but my mods aren't taking like I thought they would. I can get the error message to change, but I can't get the call to drupal_set_title to actually affect the title. Does anyone have any ideas on a way to go about this other than hacking the logontoboggan module? Is there a hook I'm not thinking of that I could call to check if a user is logged in, and if they are on a specific url to set the title and everything? Should I just be doing this in the template.php file?

Thanks in advance for any ideas.