Unfortunately, that's one of the first things I tried.

Here's the thing though (and this is the reason I added the [edit]), refreshing the fields for a Report dataset (that doesn't have a .data file already created) doesn't create a .data file. So what *does* happen when I refresh the fields? It obviously compiles and evaluates the SP in some fashion, since it does return the list of fields from one of the queries in the SP (specifically #3) ...