[HELP] Poivy (Betamax Provider) Caller ID

Hi guys! I have setup a POIVY trunk to make external calls using as CLI an italian number i previously registred on their webpage( i registred the number in the international format as requested 00390464XXXXXXXX ). Now when i make a call the caller id appears in this format 390464XXXXXX … i don’t like it because it’s neither international format ( 00390464XXXXXX ) nor national format ( just 0464XXXXXX ). How could i change my caller id in order to make it appear in the national or international format?