Added car problem

Hello,

I am using some cars with ELS for Britishpolicemods (see youtube). I used to just add them and not replace the standard models by the mods. I have succesfully added a police car but I just can't figure out how to put police people in these cars and how to put a police horn on the car. So now I want to ask ;

* How to put the emergency horn on the added car
* How to put the police people in these added cars

Thanks in advance