I'm not sure if water damaged Sony Ericsson phones can be fixed the way I use to fix Motorola and other Nokia phones. I would find the dis-assembly guide first and piece the phone up until it's completely in pieces.
Take the mobo of the phone and rinse it around in rubbing alcohol at least 190 proof and then let it dry off (it will take about 24~48 hours to fully dry) and then piece the phone back together and I've gotten the phone to work after water damage because the rubbing alcohol will knock away the minerals from regular water.
However falling into the sink while doing dishes is another story and I'm not sure if this method will work because I haven't had phones dropped into soapy water.