You can put a hostname, but I'm not sure how OpenVPN might handle that if the IP resolves to multiple IPs.
So the traffic isn't going over the tunnel at all? Or it's going over the tunnel and it just isn't going to the web site?
Or can you tell the difference since that site is blocked by IP?
You probably also need outbound NAT setup to cover the OpenVPN subnet. (It's done automatically on 2.0 but I always forget that it's not automatic on 1.2.3)