I have the same or very similar issue as Codyloco have.

Basically I've tried to setup as follows:

ISP modem -> asus router (rt-n66u, stock firmware) acts as dhcp server (I have all my home computers,printers,NAS etc connected to it -> wnrd3700, (ddwrt) on witch I wanted to run hotspot, to give short access to guests, kids friends etc.

On the wndr3700 I can connect to the internet using ath0 SSID, when I switch to the ath0.1 SSID I've got limited connectivity and no internet acces.

Is there a way to use this feature un the secondary router?

I followed the tutorials already:

http://www.hotspotsystem.com/deskpro/kb_article.php?ref=2729-IZCM-3054

http://www.hotspotsystem.com/en/hotspot/install_guide_dd-wrt.html