I want to use the mod_event_socket inbound mode to handle incoming SMS, there's a chatplan (http://pastebin.freeswitch.com/19448), and with this simple script (http://pastebin.freeswitch.com/19451) for every SMS I see two identical events (Event-Sequence with the same numbers as the other corresponding Headers do not differ from each other), is this normal?

Yes, that's normal, is mod_sms that's duplicating messages. If you unload mod_sms you'll have just one message in ESL.

-giovanni