Hi There,
Here is a Solution, but first an explanation. I am sure some folks out there have had problems with pairing the Harmony 890 pro with the RF extenders. I work for a retailer in South Carolina, the last batch of 890 Pro and extenders we received did not pair up, we even returned some as faulty to our Distributor. Finally after several calls to Logitech I was fortunate enough to talk to a technician who had a solution.
Step One - update the Firmware on both the remote and extender, do this via the support link on the harmony software home page.
Step Two - Go to the My remote link and remove all remotes from the account, plug the 890 Pro to the usb when the new remote is requested. Then add the extender.
After this don't forget to click control devices to assign them to the 890 or the extender.
Step Three - Click modify - lights - pair z wave devices and plug the 890 to the usb.
This will download a Pairing utility to the 890. NOW here is the crucial part, plug the extender into its power supply, press and hold the connect button until the status and RF lights flash, this may take up to 1 minute!!!! Release connect and follow the directions on the remote. Plug the remote back into the usb and follw the directions, the extender should show up as "paired". The Remote and Extender can now be updated with your profile.
Hope this helps.