Doors and Windows - Advice on door lite installation

We have double steel garden doors in our kitchen that lead out to the yard. The doors have a glass insert that is approximately 5 feet long. We would like to replace the inserts with a mini-blind glass insert. The only problem is that the insert we want to replace are slightly longer, lets say they are another foot longer. I know this can be installed by cutting the door to accommodate the larger insert, but my question is what is the safest way to do this and what is the best type of saw needed to cut these steel doors? Someone recommended a jig saw. Has anyone done his before? I called a contractor and they want $150/door to do this install, and I am wondering if I am able to do it myself.

Modifying your door to accept a 6' lite will only leave about 4" on top and bottom making the door very unstable. I would either try to find a lite that would fit, or opt for externally mounted framed blind units. The fit directly over your existing door lite.