Look at the end of 1st post of this thread
Those are the tools I use!
You'll need your current rom's framework-res, systemui and semcgenericuxpres apks..
Also you'll need same files from a hdpi rom that has the old Sony Ericsson look..
Decompile, copy-paste-overwrite some pngs, replace some values in xmls, recompile, make a flasheable zip and install with cwm!
Phone: Sony Xperia U
ROM: GingerBeanSS v3.5
Bootloader: Locked (Not-unlockable)