The aircraft comes with a utility panel where you select/unselect the service vehicles you want appearing when the doors (pass., cargo) are opened. To the best of my knowledge, no you can't change the door assignments for their service vehicles.
It's the best T7 on the market and it's free (can't beat that). For me it's the perfect compliment to FSDT's JFK. Basically all I'm flying nowadays are POSKY 777s and PA's Jetblue A320s. Check out there website.
http://www.projectopensky.com/