I am a firefighter myself and do this with several fire depts. Since they gave you a pager then you are in good standing. When I am taking pictures they gave me nomex coveralls and a helmet since I will be closer to the fire than the lay public. I know we gave them out to other photographers as well. We also took the photogs through a day class that actually had them fighting fires so they can understand what we are doing and not get in the way or get hurt.
To be honest I have never had a problem with my camera on a scene EXCEPT I would never change a lens because all the soot in the air. Just blow your nose after a fire and you will see!!
Also PD may not know you. I would always respect what they say if on a scene and later work it out, but since they gave you a pager that is really super. At one point I have 2 Minitor IV and 1 Minitor V and a two-way.
What kind do they have?
Pm me if I can be any more help.
My web site has some fire pics.....