Missing Data Values


I'm creating a simple plotting application.  It uses a simple 2D line
plot.  Everthing has been going fairly well but I seem to have hit a
roadblock.  I need missing values to be indicated on the graph.  I found
the MathType.missingData() method which seems to be a partial answer to
what I want to do, but I don't know how to use it.  I'm currently using a
FlatField to store my values. Is this wrong?  It is a really simple graph,
so I pretty much followed the tutorial.  The function is Time->Value.

Can someone point me in the right direction? 

Ben Monnahan