I don't believe Instant currently has an 802.1X supplicant.
For a campus AP, you enter 802.1X credentials on the provisioning screen under "802.1X Parameters using PEAP". Currently only PEAP is supported.
(master) (config) #provision-ap
(master) (AP provisioning) # apdot1x-username <username>
(master) (AP provisioning) # apdot1x-passwd <password>