Since laws are generally passed to restrict or say what you cannot do legally, there are seldom laws to tell you what you can do legally - excepting a statute/ordinance rescinding a previous no-no specifically. So short answer - there is no law authorizing/making legal OCing.
For a concise Cliff Notes guide to VA carry laws look here here.
You really should join VCDL to support and further your right to defend yourself and to keep current on the laws, events and the behind the scenes stories. Their Va-Alert email newsletter is free - VCDL membership is the best $25.00 you'll ever spend and there are members only discounts discounts.