Yes, the same like mine, i'm using freeradius too,
i tried freeradius and usermanager as radius server on MT 2.9.51, worked.
i tried freeradius and usermanager as radius server on MT 3.22, 3.21, the MT hang.
you could get the usermanager on you MT by installing usermanager package for your version,
logging in to usermanager using http://yourMTipaddress/userman
(if you still using port 80 as your http port),
create some user with pool or ip static assigned,
create router(NAS) with ip 127.0.0.1 and somesecretNAS,
pointing your hotspot profile to 127.0.0.1 and same secretNAS,
and tried to logging in the user that created by usermanager via hotspot interface.