1) You need to use the (i) equivalent of the signal for interlocking. This signal is automatic, i.e. a permissive or distant signal. You need N&W CPL HDV-R (i) RP Signal.
2) The placement is on the wrong side of the switch. You to place this signal closer to the camera on that side of the junction.
For the other tracks coming into the signal track, to form a triangle, place the signal facing back towards the tunnel and the posts facing towards the camera position. Setup all the points of the wye in that fashion.
Yes, the ability to make changes to the signal configuration is sketchy and not working, and hasn't since TANE SP3, but the signals will work in their default setup.