That´s very easy!
You have to add it to the AI-list like here,e.g.
[ailist]
0
-1
1
vehicles\Mercedes\Mercedes.bus
Now, you have to add it to a aigroup
The number there: If the bus is the first in the list, you write 1
eg
[aigroup]
name
1 (Number of vehicles in aigroup)
1 (Number of your vehicle)
Actually, it shall work
I´m sorry, if you don´t understand me, but English isn´t my first language
I hope it´s better than Google Translator
Greetings,
Bus2010