Configuring the Static NAT Mapping in CCA should work. How are you verifying if it works or not? Looking at the nat translations from your file, it appears the port forwarding is setup:
tcp 184.108.40.206:80 192.168.11.128:80 220.127.116.11:46420 18.104.22.168:46420
tcp 22.214.171.124:80 192.168.11.128:80 --- ---
This shows that the static translation is there and you have an existing translation sourced from 126.96.36.199.
If you run Wireshark on the inside server, do you see the requests coming in from 188.8.131.52?
Hope this helps.