this is mine, try it and see if it works, if it does edit it to suit your needs.
// XP Save configuration
set g_XPSave 31 //changed from 21
set g_XPSaveMaxAge_xp "5d" //changed from "30d"
set g_damageXP "0" //changed from "1"
set g_damageXPLevel "50"
set g_maxXP -1 //changed from "90000"
set g_xpdecay "0"
set g_xpdecayrate "0"
set g_xpdecayfloor "0" //changed from "1"