1. Update with SEUS and you have last SW version with CID 52 :)
2.When your phone can not update and SEUS say
Your phone already has the last software.
Downloads - K550 - Top Sony Forums
you need FS and MAIN CID 49 and flash again with XS++2.2
select your CDA and region
see in service menu when keypad is unlocked click :

> * < < * < *

Service info > Sowtware info > see Customization
CDA....
cxc....
MEDITERR

My is MEDITERR , but your may be Europe_3 , 4 , 5 or other ..
Read step by step here : K810 firmware in K800, is it possible? : Software : Sony Ericsson @ Esato
only choose your files and see screenshot's .

Then again update with SEUS and you have R6BC002 ( CID 52 )