Dual wan and dynamic dns

[Megastar]

Hi,
i have pfsense 1.2.2 with a dual wan config (2 statics IP). I have a dynamic dns with dyndsn.org. When wan fail, i would like to have wan2 to take relay and update my dynamic dns with the new wan2's public IP. I really need this feature in order to provide a continuous service of our applications.
I made some research here and someone modified some code in order to make this work. He posted his work in this topic : http://forum.pfsense.org/index.php/topic,3555.0.html
I tried his modifications but it seems those doesn't work with 1.2.2 version  :-\

Is there another way to make it work ?