Downgrade XPERIA PRO from ICS to gingerbread?

[Camela]

How can I downgrade a xperia pro mk16i from ics to gingerbread? Do I have to root the phone at first?
Where can I find the stock gingerbread rom?
How to flash it?

Thanks so much in advice

 

[stillon]

Use flashtool latest version is 0.9.22.3. This software should download another software called XperiFirm which has many xperias firmwares download options, hopefully you get mk16i gingerbread there