According to the Arbalester's description
Receive Enhancement (Ex): The crossbow built into an arbalester can be magically enhanced as if it were a normal masterwork weapon.
I also checked the description of the vanilla homunculus and it states that
They are extensions of their creators, sharing the same alignment and basic nature.
So we know that the item can be enchanted normally and vanilla homunculuses are an extension of their master. According to the description of the item familiar feat.
Choose a permanent magic item that you possess. You establish a link to that magic item, and the item improves in capability as you gain levels.
Logically speaking i feel like this should be possible however i wish to know if any ruling has been made by the WOTC or if there is a flaw in my logic?