Well thats a first for me - I didn't realise you could change the reg number that actually appears on some default aircraft?? I've changed it in the box many times however :-X
Its not too much of a job to alter them in the repaint really - I suppose you could do a complete set...! Wouldn't take too long.
Anyways, I've uploaded to SIM V just now although it took forever - and Avsim, well it never seemed to get beyond 'uploading' and didn't complete so I guess it might not appear there....something seems up at their end or mine maybe!
The only snag with inserting ones own Registration numbers/letters on the Default Aircraft fuselage is that they will not appear to others during
Multiplayer flights...

...Only to you, and during your own Solo Flights...
...in Multiplayer, all Pilots have to have exactly the SAME textures in their Hangars, for them to be seen by everyone else in the flight!
Paul...G-BPLF...but only visible to me...

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Golf Bravo Papa Lima Foxtrot.....G-B Paul Louis Fosbery...

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P.S....still waiting for it to pop up in todays "New Files"...

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Impotent Impatience should have been my middle name...

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Win 8.1 64-bit. DX11. Advent Tower. Intel i7-3770 3.9 GHz 8-core. 8 GB System RAM. AMD Radeon HD 7700 1GB RAM. DVD ROM. 2 Terra Byte SATA Hard Drive. Philips 17" LCD Monitor. Saitek Cyborg X Fly-5 Joystick. ...and a Briggs and Stratton Petrol Lawn Mower.