I don’t know exactly the limitations for WL Elements, but it should be possible in the Montage workspace. Put the (stereo?) backing track on one track, open a new (mono?) track and record into that. After recording you can mix the recorded guitar with the backing track to your liking. It is indeed more of a multitrack DAW process than an audio editor workflow, but it should work. I hope this is not something limited to full WL though…