Hi everyone- I'm having an issue with my Speedlite 430EX II- I can't get it to fire. I used it about two weeks ago with absolutely no issues. I went to use it today and it won't fire. I swapped out the batteries, made sure it was afixed correctly to the camera (XSi 450d), but no dice. I read the manual and the only other suggestion is to clean the contact points. I've done that, but still can't get the unit to fire. I figured maybe someone here might have some experience with a similar issue and some suggestions. Any help for the new guy would be much appreciated.