Yes, that is possible, but not within the wizard.
Create the WLAN via the wizard and than you have to configure a new AAA Profile for that WLAN VAP.
Go to the right top corner - "admin" - "Preferences" - set the hook to show advanced Options
Than go to the WLAN SSID - right hand "Profiles" - ... - AAA and set the ClearPass AAA Profile.
This has to be configured beforehand if not already done.