You should be able to connect this signal repeater using Touchlink just like a light. See the following: How to connect lights using Touchlink in Hue Essentials?
A reddit user was able to pair it successfully, see: Anyone using an IKEA Trådfri Range Extender with Philips Hue?
I plugged it in next to my bridge, like 10cm apart. I used the android app “Hue Essentials” to trigger Touchlink on the hue bridge (Lights → Add → Select Bridge → pressed “Touchlink” and afterwards press “Search for Lights”), I read that other people have used this method successfully for linking IKEA motion detectors to hue. Did nothing, then I repeated the steps but I hit the “Touchlink” button like 6-7 times repeatedly and then pressed the search button in the app. After this the LED on the extender stopped blinking and the LED was now constantly on. I reseted the extender as I though I may have just reached some sort of timeout in the device itself because it was waiting so long for pairing, but I could repeat the steps with same result, so the touchlink approach did something and it seems it is now paired with my hue network.