Hi Gladbach
Maybe you'll have to find another way....
DAQ boards are meant to be used for sampling
generic signals, opposite to
periodic signals. A scope, usually, rely on the fact that signal to be acquired is periodic, and this allows some way to perform down-sampling (provided you have a frequencymeter, to determinate signal frequency first! In digital scope you have it).
NI provides a different family of products for building scopes: they're the High-speed digitizers,
http://www.ni.com/digitizers/ . They're quite expensive, but it's almost what you need. And with a digitizer board, you also get NI-SCOPE.
Hope it helps....
graziano