Yes, it can be used this way subject to the router's support of forwarding a port to a broadcast address.
In general, there would the following steps:
- Make sure WOL is configured at the target PC and can be woken up locally from the same network.
- Add a WOL entry in the Network Scanner application. If your router has a static external IP address, use Add - IPv4 Target. If not, the router needs to be configured to work with a DDNS service like DynDNS, so it can be accessed by a domain name. Once done, use Add - Host Name Target.
- The router needs to be configured to forward incoming packets to the port configured in the above step to a broadcast address like 255.255.255.255 or x.x.x.255.
Here is how it's supposed to work:
- A "magic" WOL packet containing the target's MAC address is sent to the router's external IP address.
- The router forwards and broadcasts that packet within the LAN.
- A computer with the MAC address from the WOL packet wakes up.
Unfortunately there can be issues regarding router's support, but here is a couple of articles that can help:
How to Remotely Turn On Your PC Over the Internet,
Wake-On-Lan through the internet.