Since they have captcha before you can even view the links it won't be possible.
If they didn't had captcha you could add to dead keywords:
Code:
offline_detail.png
And it would be fine.
I would suggest:
* To use different service (I personally would find annoying to solve the captcha every time I click on your links and it seems could be a cause of less downloads overall).
* Also those "relink" links doesn't have filename in URL so it will be much harder to replace them when needed.
* Just put the normal hosts links in the message.