[Freeswitch-users] anti SPIT mechanisms

Hi, today I got my first automated SPIT call over my ekiga account. So I looked for anti SPIT mechanisms in freeswitch´s wiki and found http://wiki.freeswitch.org/wiki/Mod_limit Well, it only limits spit calls. So I looked further and found that asterisk script: exten => 123456,1,Set(pin=${UNIQUEID:-2}) exten => 123456,n,Playback(your_password_is) exten => 123456,n,SayDigits(${pin}) exten => 123456,n,Authenticate(${pin}) exten => 123456,n,Goto(some_context_ring_ring,s,1) So, let the caller repeat a random number and has to prove that he/she is an human. Well, has anyone done something like this or better mechanisms within freeswitch? Chris