Yea correct only E2000 is acting as a Hotspot AP. Ive managed to get it working in diffrent way.
ac66u with his dhcp etc is not touched. All settings are on E2000 so to start with
I setup E2000 within the same range as ac66u. I set DNS to 8.8.8.8 and gateway pointing to ac66u. Of cource DHCP and all 3 ticks on E2000 are disabled. Wireless network is unabridged with Multicast and Masquerade Enabled. I put in IP section 192.168.20.1 with netmask 255.255.255.0 and it started to work. Im getting slash screen etc. I have tried latest builds with partial luck. HSS is getting configured but redirection to splash screen is not (ddwrt bug http://svn.dd-wrt.com/ticket/5476) so basicly build r22118 is fine to setup HSS on second ddwrt device in the same network