Sorting Parameter values in SSRS Model based report

This is by far the best answer (provided by JohnMKelly) I could find - it worked perfectly to sort my parameter drop down list.

I tried setting the SortDirection in my Report Model (as suggested by Zeilo), but that had no effect.

But if I can suggest one other option (for Report Builder 3.0): Create a Shared DataSet. For example, I created a Share DataSet for my clients. The DataSet returns a Client ID and a Client Name. I even provide it with a parameter: isActive (1=Active, 0=Inactive, 2=Both Active/Inactive). To produce the results, I developed a query and ORDER BY Client Name. With the Shared DataSet, I can easily reuse and ensure all ad-hoc reports show the exact same parameters.