I want to use the API to change a drawing's balloon numbering from 1, 2, 3... to 5, 10, 15. I have existing balloons, and want to update their numbers. I can't find the necessary API methods. I found IBomFeature.SequenceStartNumber, but I don't see anything for the increment. Am I missing something?
I also found IBalloonOptions.ItemNumberStart, and .ItemNumberIncrement, but I don't think that's what I want, since it seems those only apply when adding new balloons and I want to update existing balloons.