Which version of BTB are you using?
rFactor defines the Safety Car as [AUX] in the AIW file but GTL / GTR2 / EVO do not utilize [AUX] in the AIW. SimBin AIW file include the Safety Car as the final entry of [GRID] "GridIndex=103" + [TELEPORT] "GridIndex=103" + [PITS] "TeamIndex=51".
Below is an example of Safety Car positioning at the same track:
Note that XYZ is the same, but definition in the files is not.
"WillowRaceway" AIW File (rFactor)
[AUX]
LocationIndex=0
Pos=(-2.607,0.086,-0.120)
Ori=(0.028,1.567,-0.000)
LocationIndex=1
Pos=(-83.432,2.678,-27.444)
Ori=(0.001,3.134,0.026)
"WillowRaceway" AIW File (GTR2)
[GRID]
GridIndex=103
Pos=(-2.607,0.086,-0.120)
Ori=(0.028,1.567,-0.000)
[TELEPORT]
GridIndex=103
Pos=(120.0,-1.271,-2.058)
Ori=(0.019,1.579,0.001)
[PITS]
TeamIndex=51
PitPos=(-83.432,2.678,-27.444)
PitOri=(0.001,3.134,0.026)
GarPos=(0,-83.432,2.678,-27.444)
GarOri=(0,0.001,3.134,0.026)
GarPos=(1,185.855,-0.938,-39.793)
GarOri=(1,-0.002,-0.789,0.002)
GarPos=(2,0.000,0.000,0.000)
GarOri=(2,0.000,0.000,0.000)
I hope this helps..