in some way i did it....
i repeated the tutorial 4 or 5 times, and everytime no italian at all...
last time, i got crazy, i added also hong kong chinese... (would be nice to have both.. hehe)
and from allowed_language.txt and customize.xml i removed 2 languages i will never use from the list....
and added IT and ZH....
close everything, turn on the phone... still nothing...
then i did a MASTER RESET from the menu...
and after it... ITALIAN appeared and works!!! (as SMS language but not as phone language... but is ok) but no hong kong chinese.... i tried the chinese and its the one i had before.. pity!
but is strange, why italian works after the master reset and hong kong chinese doesnt? seems i have to convince my phone to do what i want, not only follow the guide, is it human? ^^
anyway im happy enough, except one thing...
the problem i had in the begin.... still come...
once per day (more or less) the wallpaper and the ringtone will disappear....
and the menu cursor will be a black square...
but now, i guess is an hardware problem.. =)
i will have a try to add again hong kong chinese... and if can, i will post the result...
by the way, should i add the winning steps in the first post? to make a kind of poor "guide" for the same kind of problems i had?
and finally, thanks to the website and to everyone who helped me in this adventure.. and of coz, thanks a lot to Hyperion!