If you have a router on the local network (Considering a home network), why not access the router (which hooks you up to the internet) and let it send the MagicPacket.

For example the Fritz!Box is able to send WOL calls via a build in GUI.

There are modified firmwares for the vast of routers out there which enable them to to do the same (if not out-of-the-box)

This would be a way around.

Another way around is to access a PC in the local network via VPN, SSH, ${WHATEVER} to send the WoL signal (as jaark already implied)

Cheers
Bjoern