Sorry I don't follow you, regarding the rfm and custom u.i you have? Editing the rfm is internal.
Just for anyone else reading, each rfm, for example 'Reiza01' is for the Stock V8, 'Reiza07' for the Formula Reiza etc - they are in order of how they appear in the game menu to select the car class. In those rfm's, copy/pasting the track name from the VERY TOP LINE of the .gdb (in locations/<track name>/track/.gdb) into the rfm where the tracks are listed (Scene Order) will mean the game will load that track in the corresponding order, so very good for custom championships. ('Notepad ++' not normal notepad). You can change the tracks at anytime, just restart the game, or exit to main menu/reload; if you removed one, or opted for a different track choice for example, it will just load it as if nothing changed. I use to use Championship maker, but once you select the track, its set in stone and can't be changed. I wish Reiza would tell people this as choosing your own championship is vital to immersion and tailoring.