Im using neo v with KA04 ICS and use from face unlocking to unlock screen in my phone.
It's usefull, cool and smart as i know you
To enable face unlocking in neo /neov you need this ROM: Rom Neo/ Neo V 03/03 Fast & Stable|KA04 Ice Cream Sony
1.go to setting >> security >> screen lock >> then choose face unlocking
now give your face on the line that show in screen and let phone to detect your face. OK man u success to enabling face unlocking
2.to improve face matching do to setting >> security >> and tap on Improve face matching. you can try this section to 2 or 3 again to imrove it.