A 'source' as in: the entity that says the text line. The text of your holo scroll will always appear to originate from your holo scroll; you wouldn't be able to make it appear to originate from another player or entity.
Well that's easy, i just have to create another account name for example "NPC" and "You" so that the convertation don't start with "Angelio : Npc : Blablabla..."
Angelio
Firefly
