VC panel not transparent...

OK.. me again on a VC dilema. I'm hoping it's just fatigue (been working on this for 8 hours straight) and I'm missing something obvious..
Just testing the whole procedure to get a feel for gauge placement and what-not.. I've come up with this...

Hopefully, this explains my question all by itself ::)
I made a square polygon, facing the pilot, right in front of the static panel (which I was hoping would serve as the background image, and then I'd just "decal" the active gauges in front of it).
I then applied a 1024X1024 texture (pa31_vc1.bmp) to this polygon. Then, globally renamed it "$pa31_vc1" (adding the $ prefix and removing the bmp extension),,
Here's my panel.cfg entry for the VC:
------------------------------------------
[VCockpit01]
size_mm=1024,1024
pixel_size=1024,1024
texture=$pa31_vc1
background_color=0,0,0
visible=0
gauge00=KingAir!Airspeed, 300, 600, 200, 200
-----------------------------------------------
I'm just supposed to see the gauge, right ?
That annoying polygon is supposed to be invisible.. right ?
What have I overlooked ?
Just testing the whole procedure to get a feel for gauge placement and what-not.. I've come up with this...

Hopefully, this explains my question all by itself ::)
I made a square polygon, facing the pilot, right in front of the static panel (which I was hoping would serve as the background image, and then I'd just "decal" the active gauges in front of it).
I then applied a 1024X1024 texture (pa31_vc1.bmp) to this polygon. Then, globally renamed it "$pa31_vc1" (adding the $ prefix and removing the bmp extension),,
Here's my panel.cfg entry for the VC:
------------------------------------------
[VCockpit01]
size_mm=1024,1024
pixel_size=1024,1024
texture=$pa31_vc1
background_color=0,0,0
visible=0
gauge00=KingAir!Airspeed, 300, 600, 200, 200
-----------------------------------------------
I'm just supposed to see the gauge, right ?
That annoying polygon is supposed to be invisible.. right ?
What have I overlooked ?