Vampires and Gaseous Form

It's always fun when trying to handle half-remembered rules in the game, especially when in the context of an extremely complex high-level combat. Basically, there were a few calls made regardiong the vampire in the last combat on Saturday that weren't quite right:

1) The Turn Undead attempt against the vampire should, indeed, have failed. The creature's hit dice were too high to be affected. Oh, and the wraith was specifically immune to turning/destruction due to a class ability.

2) The last attack against the vampire, the one that reduced her to 1 hit point, should actually have reduced her to 0 hit points, and forced her to take gaseous form immediately. Since her next action was to do just that, there was no harm done.

3) Once in gaseous form, the vampire is specifically immune to any further damage (although, I suppose, she could have been destroyed by a greater turning or similar effect). However, the vampire also has a mere 2 hours to reach her coffin, or else is destroyed. This reflects the classic ability of the vampire - they must always be hunted down and destroyed in their own domains.

So although it might have seemed like I was twisting the rules into knots to protect that character, I wasn't quite doing so. I just wasn't applying the rules quite correctly.