I was not able to define the RemoteLinc device using the second add option, specifying a device name and the Insteon ID, under Harmony. Not sure if this is due to the lack of a Set button on the RemoteLinc. I was able to define the Remotelinc using Harmony by selecting the 3rd add option, specifying a device name, Insteon ID, and selecting the Smarthome RemoteLinc as the device type.
I was not able to define an Action that would trigger from a RemoteLinc button using Harmony. I was able to define an Action that triggers from a RemoteLinc button using the HTML interface. This particular Action triggers from RemoteLinc button 5 On (1105). The attribute value would be 1103 to trigger from button 3 On. The Action Effect 1 turns on an X10 device and after a 5 second delay Effect 2 turns the X10 device Off.
Be sure you have linked the RemoteLinc button of choice as a controller to the EZSrve as a responder. This can be done by creating a Scene where the RemoteLinc is the Controller and the EZSrve is the responder.