Hope this will save somebody else some time.  There is a Joe Kunk webinar and while the technique of using a SQLDataAdapter is seductive, it doesn't work as shown.

Here's my solution :

http://www.devexpress.com/Support/Center/p/Q299515.aspx

Basically, you need to set the param and call the fill in the BeforePrint(), and be sure to reset the design-time sda param before you build (or export your reptx )

This was a head-scratcher but it is working great now - recommend you give it (and DevExpress in general ) a try.