The Controller Unit number used in the Scene where the RemoteLinc is the controller has to be the RemoteLinc button (Group) number, 03 in this case.
For Insteon hardware to send a Group command sequence from one device to another the devices must be linked together. Smarthome uses the term Scene for this relationship. In its simplest form a Scene (also referred to as a Group) consists of a link record in the Controller device (RemoteLinc in this case) which points to a responder device. The link record also contains a Group number which corresponds to the button number on the controller. When you press RemoteLinc button 3, the firmware in the RemoteLinc searchs its link database looking for a link record that has a Group number that matches the button number that was pressed. If a link record with that button (Group) number exists the device address in the link record is the address of the responder device to be controlled. The responder device (EZSrve in this case) has a link record which contains the address of the controller device to which it should respond as well as a Group number that matches the button number in the controller. This is standard Insteon architecture. So far nothing is unique to the EZSrve. The same Scene would have to be established if a SwitchLinc, as a controller, is controlling LampLinc for example.
A Group command sequence sent from a controller to a responder contains the Group number of the button that was pressed and a command indicating what action to take. The value 1103 indicates an Insteon On command (0x11) and Group (button) number 03. The Action definition specifies the Device, the Insteon command, and the Group number which causes the Action to trigger. All the information has to match for the Action to trigger. The Scene (links) must exist for the Insteon hardware to send the Group sequence to begin with. In general if a controller does not have a link record defined for the specific button pressed, no commands are sent. There are some exceptions to this, there always are, but for this situation it is a requirement.
The Value of “2” for an X10 device in the Effects represents an X10 On command. A Value of “3” represents an X10 Off command. There is a chart in the EZSrve User Guide which contains the values for the various X10 commands.
Hope this helps. If something is not clear let me know. Also on the Smartlabs web site there is a rather old but still relevant Insteon Detail document that explains how the Insteon hardware works. Lots of new things have come down the road since that document was published, much of which Smartlabs (and Smarthome) consider confidential and proprietary but some of the new stuff leaks out. The Smarthome forum is a good forum to follow.