For the moment it is not possible.
pfSense frontend doesn't have that option and the backend doesn't have it too.
I've been doing some testing with Kiffuser as you can see here…but so far no good. Have asked for some advice but no go too, it seems wireless development is for some reason in standby when it comes to authentication methods.
I think we already got somewhere but we haven't had much time to go anyfurther, maybe in the next weeks.
The easy part is making the frontend thing, which is creating the interface for the radius settings...our problem know is putting the correct values in the $config["wireless"]["…"] array…so it can pass the correct settings to hostapd_ath0.conf and save the configuration XML.
For now we're getting a pretty messed up hostapd_ath0.conf, as there are some settings needed that we can't get from $config[] var. In here, at the bottom you can see an example for what is needed in hostapd_ath0.conf, but so far we haven't been successful.
If you or someone else have something that could help, or if something that i said is wrong, please correct me.