You're sure that it's a rescue email address that you have, not an alternate email address ? If you aren't getting the reset link then that indicates that your don't have a rescue email address, and you won't be able to add one until you can answer your questions - you will need to contact iTunes Support / Apple in your country to get the questions reset.
Contacting Apple about account security : http://support.apple.com/kb/HT5699
When they've been reset you can then use the steps half-way down the HT5312 page that you posted from to add a rescue email address for potential future use