tremolo's in the Grieg Concerto

[tony]

Guys, in teh end the tremolo's near the end of the cadenza how can i go about creating that FAST feel... almost trill and legato like.. my teacher syas ur hand needs to be firm.. but how can i go about it? also the measure right before those last two withe the f, G#,b d tremolo int eh r.h.
thanks guys!@