Possible? Inbound (WAN) look at NAT, other through OpenVPN

[m-snel]

I have a Synology NAS that has (among others) a download center and also a webserver on it. I also have a OpenVPN connection (commercial VPN) running on my DD-WRT router.

When the OpenVPN tunnel is active, the sites on my webserver can't be reached through the domain (which is linked to the static public IP I get from my internet provider).

This can be solved by using the policy based routing field of OpenVPN, but then the NAS completely bypasses the VPN connection (which off course is not wanted with for example the download station).

Ideally would be if all outgoing traffic (and inbound traffic as a result of this outgoing request) would go through the tunnel and incoming traffic on the wan port is analyzed. If there is a nat rule for this port in the routers nat -> forward it directly to the specified IP address as stated in the NAT (without using OpenVPN), if not do use the tunnel.

Does anybody know if this is possible (and if so, how) so I can use both the webserver (using my static public IP) and the rest through OpenVPN. As the IP of the VPN changes regulary (which is off course the idea of such a VPN) it isn't possible to forward the domain through the tunnel. Also this would off course be a security issue as the domain holder could be linked the the VPN user then.