Protovis bullet chart boundaries

I have been looking for ways to change the default lowerbound in P开发者_如何学Crotovis Bullet Charts to something else than 0. It seems to be impossible, but I would love to get some confirmation of that. (Or actually, I would prefer to have a solution instead.)

Same for the direction of the ranges. By default, it increments from left to right. I would love to be able to turn that around: decrement from left to right. Again, it seems it's impossible, but I may be missing the point.

I eventually started out changing Protovis myself. It works to some extent, but for more complicated cases (like cases in which you want the scale to run down instead of going up), it's getting really awkward. Eventually I ditched Protovis and started using Raphael instead.