not heard using eap-pap for wireless users authentication unlike what we hear common eap-peap, eap-tls, eap-ttls. since we use externall aaa, we shall try with 802.1x configuration on wlan profile. please share your observation once we try it.
no special settings we need, just configure wlan with aaa configuration i.e. add external aaa server with authentication mode set to wpa2-enterprise / wpa2-802.1x.