Might be wrong, but there is a line in the [CONTROLS] section of the "main" cfg file. The name is whatever your icon for the sim is. For example, my exe file is CFS2_PTO and the cfg file is called cfs2_pto.cfg. It is located in the main CFS2 folder you have.
Here is an excerpt from my cfg file:
...
[APL]
CACHE_WAV_FILES=1
[CONTROLS]
force_master_gain=10000
force_stick_force_enabled=1
force_stick_shaker_enabled=1
force_gear_bump_enabled=1
force_crash_enabled=1
force_ground_bumps_enabled=1
force_machinegun_enabled=1
force_bulletdamage_enabled=1
force_rocket_enabled=1
force_bomb_enabled=1
force_flak_enabled=1
PAN_RATE=400
[MULTIPLAYER]
TICKS_PER_SYNC=90
...
Your PAN_RATE=400 won't be in bold, I just did that to help you see what you are looking for. Best way is to Ctrl+F and type PAN_RATE and you should be good to go.
If you want it slower decrease it and faster just vice-versa. Be aware I've never messed with this, so just be careful how much you change it either way.
I compared the cfs2_pto.cfg file to my fs9_classic.cfg file and the pan rate control line was the same, so you can use this pan rate entry for FS9 if you have that sim set up.
Good luck!
Jorge
Miami, FL