If the data is relatively slow then generate an array to store all of your points (same number as displayed on your chart) and for each new point acquired, rotate the array and replace the last element with the new point and update the waveform graph. Then you can have the cursors you want, just a bit of extra data manipulation.
Mike
From the 2012 home of the Olympics National Instruments UK will be donating an official Olympic polo shirt as a prize
Looking forward to seeing y'all (Got to practice my Texan)