The RemoteLinc remotes, to save the batteries go to sleep and will not respond unless; as you found are in the Linking Mode.
Using HouseLinc Desktop. I also could not find mine; even though I added the 6 digit ID manually.
Some have indicated if you hold the Bright-Dim combination bottons for 10 seconds; it will also wake up. I tried that combo and it did wake up. Note this combo is also for turning on and off the beeper or LED. So if used do not use the Bright Button alone or the All OFF Button to get out of the mode. I also found it will time out in 4 minutes