You might try messing around with the Arpeggiator... you might find something that comes close to the sound you're looking for.  You can tweak the timing and velocity a bit in the Arpeggiator window.
 
BUT... if you really are serious about getting a good trill/tremolo sound (strings, woodwinds and brass), save up for EastWests Symphony Gold...

A wind controller may help but it mostly comes down to the samples. I think Dim Pro has at least one patch with a decent trill. I may have an example of it in use

Here is an example of that patch in use for a xmas song I threw together last year:http://soundcloud.com/eta...ess-ye-merry-gentleman