Need to turn Data Connection OFF (really Off!)

[DLCPhoto]

I'm heading out of the country in a few days, and to avoid unintentional data charges, want to turn Data off. I know where to do this in the usual Communication Settings area, but as we know, this is only a temporary adjustment. As soon as some program wants to access the internet, the Data Connection turns itself back on.

How do I turn if Off so that it won't turn back On by itself? I imagine this is to be done in the Advanced Settings area, where the various Networks are listed, but am a little uncertain as to exactly what choices to make there so that I don't unintentionally incur exorbitant data charges.

Thanks!