You won't find such a statute, because laws don't permit, they forbid. Since we're talking about a legal activity, we should expect not to find laws addressing the subject.
The relevant statues are Virginia's concealed weapons statues:
As for the seatbelt query, there is still no consensus. One argument goes that, if you sit in a booth in a restaurant you have not concealed as you made no attempt to conceal the weapon and any change of position will reveal it, so why shouldn't this work in a car with regards to the seatbelt as well? The other argument goes that a seatbelt comes too close to covering the gun like a garment would, so this is concealed.
Perhaps someone can share the most recent thread with this debate. I failed to locate it.