You dont need to adapt any of the system files in order to have another clients login screean. Just search a bit for custom login screens and try to find what changes on utx & textures if you can't find it then request again for help I am gonna do it for you.
First don't spam it's in Greek can't you see ? Warned.
Secondly
Auto einai related quest kai exei na kanei me java. Ean theleis na forane oi aploi chars ta hero weapons vriskeis ta ID apo hero weapons kai ta ksanapernas sto weapongrp.data me diaforetiko ID kai diaforetiko name. Meta pernas ta sql sthn db kai ta xml sto pack.
E wraia vres xml apo ala items kai alakse id kai onomata tha pas gameserver/data/stats/armor ekei tha breis kiala xmls apla kane kainourgio me ta ids pou exoun ta wings sou.
Try to change the numbers and see using pawnviewer what happened when you change a number but for what client are they ? They are already shared for interlude , freya and hi5 so you might waste your time with them.