cifs over wan

Hi, I can't get cifs working over the internet. Works over lan.

Here is the situation (fake numbers but in line with reality):

My home ip: 208.67.15.123
My routers LAN side IP: 192.168.56.1(Static)

My computers nic ip: 192.168.56.30 (Static)
My virtual computers nic ip: 192.168.56.31 (Static) (A virtualBox installation of omv using bridged networking).

ROUTING:
-omv (192.168.56.31) can be reached via ping and cifs from any computer in LAN.
-in router i port forwarded port 445 to point to computer 192.168.56.31.

Security:
-On host computer no firewall. No security soft.
-omv is what it is when you get it as a virtualbox image for the most part.
-the laptop that tries to connect to omv has no sec software or firewall.

When I'm not home i try to connect to cifs share as such \\208.67.15.123\MyShare\
and it times out. I use the Win 7 GUI so this is the map share to drive button in Win 7. I select use different credentials and type in Username and password when prompted...

Any ideas?

Fair enough. How can I use VPN with omv?
That is something that is setup and configured server side, no?
Since the server is omv, I need omv to have a vpn feature, no?

I'm not a Linux ninja. What do you guy suggest?

Should I do apt-get openvpn at the omv command line or what?