Latest Sony Ericsson arco IS11S user agents:

User Agent	Browser	Platform
Mozilla/5.0 (Linux; U; Android 2.3.4; ja-jp; SonyEricssonIS11S Build/4.0.1.B.0.118) AppleWebKit/533.1 (KHTML, like Gecko) Version/4.0 Mobile Safari/533.1	Android Browser	Android 2