I just published an updated version of the Wake on LAN (WoL) client for webOS (Palm Pre and Pixi). The latest version supports specifying a custom hostname and port, which means that now you can send WoL packages from to a remote network.
James Knowles (please see the about screen for contact info) contributed the initial UI changes for specifying a hostname. I added some more information and added the ability to specify a custom port (which required a service update).
To get these changes please update to/install the latest version of the service and UI using Preware.