Based on your entry it appears that you have the ST25A XUST25BAWH model. Please note this for future reference.
Model: ST25A - This model can be found on the Sony Mobile Phone Support Site
Model: XUST25BAWH - This model can be found on the Sony Mobile Phone Support Site
NOTE: You may need to refer to your product again to determine the actual model name.
TIP: Model Numbers are usually located on a sticker located on the back or bottom of the unit. They may also be listed on the product manual.
For VAIO® computers, click here for additional information on locating the model name.