Phone [Q] sony ericsson acro (au by kddi)

sorry if i posted my question in a wrong thread or place.

my aunt gave me a sony xperia acro (au by kddi) which was from japan. i was trying to unlock it myself but still no luck. i've searched everywhere. so is it possible to make it work here in Philippines, like sending sms or for calls?
or is there a custom firmware?
could someone please give a tut.

thanks in advanced