Well i tried to configure openVPN using my default WAN adapter. I had some weird issues, i got errors after configuring openvpn and pfSense admin page displayd some filter reload erros. Also after restart i had no internet connection on my lan devices.
So i took the openVPN server down and removed all the firewall rules and did a fresh restart. After that, when i set up openVPN again, on the default WAN interface, at lease i got it to work.
Weird is also the fact, that this is almost a fresh installation, i havent really configure anything.
I think this was the issue with the virtual IP also, but i am going to reconfigure the openVPN when i have enough free time.