How can I specify the default tab in a CHM Output?

My company uses CHM-based help for some of its products. We build the CHM files from RoboHelp 9, and while these CHM files don't really have a full Index attached to them, the Index tab shows up in the output anyway. Unfortunately, we are suddenly seeing that when the CHM file is launched from our program, the Index tab is displayed by default. We'd rather have the Contents tab be the default look, especially considering that the Index does not exist.

I have poked around into how you can specify a default tab for a CHM file, and the only information I have found suggests that using a CHM file creates a file (HH.dat) that specifies which tab should be displayed on a user-by-user basis, and that the last tab displayed when you close the CHM should be the first one displayed when you re-open it. While this is true if you open the CHM independent from the product, when you launch it from our program, it's all Index, all the time.

So, my question is: How can I specify the default tab for a CHM file? Or, failing that, how can I excise the Index tab from my CHM output.