Lighting suggestions

[susieraeo]

Does anyone have any suggestions for the following scenario:
I am taking portrait shots for our local fire dept. These are the formal wall photos in full dress uniform. The shot is framed from the waist up. The person is sitting to the side of the fire engine in front of the shiny metallic gauge panel.
I have plenty of room to work.... the only lighting is from the large garage door in the front and some overhead florescents.
What I have so far is 2 18" portable lights with plastic diffusers and I can also add umbellas to those. I also have a 36" portable reflector panel.
I'm using a Canon Digital Rebel.
any suggestions as to light placement (how close, etc) and whether or not to use my mounted flash?
I'd appreciate it! Thanks,