First i would confirm the texture folder name and what is in the aircraft.cfg

here is mine from the aircraft.cfg

texture=fedex_RR

and the folder name is texture.fedex_RR

Remember if there is no thumbnail then dont look for the image of the aircraft, as long as those two match it should show up so confirm you have the folder in the cs 757 200 F folder in simobjects/airplanes.

Because it is made for FS9, things are a bit different in the description.txt so it is entered into the aircraft.cfg wrong. Although this is for the David Sweetman FS9 757 Freighter FedEx RR, the same applies to the FedEx PW.

[fltsim.2]
title=Captain Sim 757 Freighter FSX Paint1
sim=cs757-FRR <---- this is wrong
model=RRLWL <---- this model doesn't exist, so you wont see the aircraft
panel=
sound=
texture=fedex_RR
kb_checklists=
kb_reference=
atc_id=N757FE
atc_airline=Fedex
atc_flight_number=N757FE
atc_heavy=0
atc_parking_types=
ui_manufacturer=Boeing
ui_type=757-200 Freighter RR
ui_variation=Fedex
ui_typerole="Commercial Airliner"
ui_createdby="Captain Sim"
description=Repaint by Dave (Dax) Sweetman. Please feel free to send me comments. Email davesweetman@onetel.com
visual_damage=1

So change it to this:

[fltsim.2]
title=Captain Sim 757 Freighter FSX Paint1
sim=cs757-F
model=RR
panel=
sound=RR
texture=fedex_RR
kb_checklists=
kb_reference=
atc_id=N757FE
atc_airline=Fedex
atc_flight_number=N757FE
atc_heavy=0
atc_parking_types=
ui_manufacturer=Boeing
ui_type=757-200 Freighter RR
ui_variation=Fedex RR
ui_typerole="Commercial Airliner"
ui_createdby="Captain Sim"
description=Repaint by Dave (Dax) Sweetman. Please feel free to send me comments. Email davesweetman@onetel.com
visual_damage=1

(red text is the changes made) and you should see it.

Mark

Edited: