it is possible to manage the routers using VPN0. That said to do this you would need to open up SSH using allow-service. This would be a serious security issue and leave the router open to attack from the internet. it is best to use vpn512 for management. I have seen several routers with SSH open on internet circuit and usually you will find it isn't long before you will see dozens of login attempts per minute. I suggest you follow security best practices to avoid any problems.
