The red light ticket crap is just that - crap. They say it's a civil penalty against the owner of the car, not a moving violation penalty against the driver. It's a legal tactic that allows them to indescriminantly send out tickets without actual proof or the 'burden' of guilt. I just got me first one about a month ago, I was pissed, I wanted to fight it, I researched it, and then I paid it. The cards are stacked too high against you, as you found out.
Worst part about all this is that the city of Houston had a referendum, and 60% of the people voted against red-light cameras. So they turned them off. For the past six months. Now they're back on. READ:
http://www.thetruthaboutcars.com/2011/07/texas-federal-judge-again-blocks-defense-of-houston-anti-camera-vote/