reg number in stock aircraft

Greetings all
I have been repainting with acceptable results for my VA. I am now attempting to repaint the stock 737-400
The results were acceptable until I went to fly her. I have the reg numbers on the vertical stabilizer, but the black MS700M is on the aft fuselage. (the number is the same as my reg number after I edited the aircraft.cfg)
How does one find the spot to get this "tatoo" removed?
I have been repainting with acceptable results for my VA. I am now attempting to repaint the stock 737-400
The results were acceptable until I went to fly her. I have the reg numbers on the vertical stabilizer, but the black MS700M is on the aft fuselage. (the number is the same as my reg number after I edited the aircraft.cfg)
How does one find the spot to get this "tatoo" removed?