For plots of type: point, waveform, X, XY, Y, you can use the different line styles available, either while plotting (in the correspondent Plotxxxxx function) or after plotting via the SetPlotAttribute function (ATTR_LINE_STYLE attribute).
The line styles available are: solid, dash, dot, dash-dot, dash-dot-dot. Up to version 5.5 it's not possible to obtain other patterns.
Roberto