Right, who's network is it... If it is a corporate, or has any existing infrastructure at all, you will probably need to arrange access through their IT department... (lottery....)
If it's standalone (PLC PV+ and router only...), becomes a bit easier... The best way I have found is to use a VPN router. On connecting with an appropriate client from your PC, you can access all devices on the remote network... Can be a single box, or if there is already a router, can sit a VPN router behind.
Couple of gotchas... Need a static public IP address on the internet (or subscribe to a DNS service to find..) and need to set the PLC & PV+ default gateway to the router internal IP.
Bit more to it than that, but not much...
