Then, open up the "aircraft.cfg" files of the respective aircraft and input the following text after the last aircraft entry, before [General] and after the description of the last entry. Change [fltsim.xx] to the next corresponding number (for example if the last entry was [fltsim.2] you would input [fltsim.3] replacing the xx with the number 3).
(If it does not open initially, right click the *.cfg file and select "Open with..." and select "Notepad")
title=A330-300 SriLankan Airlines
description=Sri Lankan air lines livery for Thomas ruths Airbus A330-300 by Dulshan Wijayasinghe.