Tried that, didn't work, however...
Hopefully I understand you correctly. The test set up I used was two long open ended pieces of track connect by the one turn out. The signal with the feather was place between the engine and the turnout. This, of course, didn't make the feather illuminate. Non-feathered signals were placed on the other side of the turnout, but the feather would still not illuminate.
I got a hint the other day that the track (the "mainline") needed to be connected to itself, like the typical toy railroad layout. So I made an oval of track and placed in the feathered turnout to a spur of track (open ended spur of track). If I recall correctly the feather still would not illuminate. It wasn't until I connected the open-ended spur back onto the mainline that I saw the feather light up. FINALLY after about 40 hours of struggle, I saw some signs of success.
I appreciate hearing more of what you have to say on this. I'm relatively new to TRAINZ and still learning. I've not heard of invisible signals, and I'm still trying to figure our what triggers do. Plus there are more signals that seem to have no usefull function.