Hmm. Ours has oem glass screen, but it was my understanding that on plastic screen models the wiring was installed and all you needed was a switch and relay to make the hrw work.
The longer I'm on this forum the more it is apparent that all TF were not created equal. For example, ours has an auto central lock feature that activates at 20mph: which seems rare when talking to others.
Not an epic task to wire in the necessary for your rear screen. Fiddly though.
It will be all right in the end. If it isn't all right yet, then it is not yet the end..