Even better, after some quick searching we managed to obtain its user agent that gives away some juicy details about this new Xperia phone.
To start with, the ST18i (which seems to be codenamed “Azusa”) is a GSM handset running the latest version of Android for phones - Gingerbread, has a Cortex-A8 processor and a resolution of 480 x 854.
It's obvious from the leaked pics that it has two cameras (the rear one has flash), as it's also obvious that the ST18i shares some similarities in design with the Sony Ericsson Xperia mini.
That's the certain part, but rumor has it (according to the Chinese site ZOL) that the Sony Ericsson Azusa sports a 3.3-inch TFT display and will be launched this month (presumably in China).
source: Sony Ericsson and ZOL via SEMC Unofficial Blog