I think we never tested wan connection using a wifi interface.
Probably we’re missing some parts of the configuration.
Could you please try following CentOS instructions?
http://wiki.centos.org/HowTos/Laptops/WpaSupplicant
You’ll need to install wpa_supplicant:
yum install wpa_supplicant
If you report success, we could file an issue and try to implement a new feature.