Advice on DS212 + ASUS RT-N66U + DSM 4 configuration

[nfilg]

Hi! I need some advice on how to set up my DS212 so i can access it remotly, via browser.
DS212
+ ROUTER ASUS RT-N66U
+ SOFTWARE DSM 4

I have two domains that I can use to for a static IP.
I've tried the ez-internet with no success, can you help me with this. At the moment I can access the diskstation at my home netework via WI-FI with an IPAD synods and with my laptop via wi-fi too.
Everything works fine on the home network but not outside.

Thanks.