If you're using CNiGraph (or CWGraph), there is no direct support for this. Probably the easiest workaround would be to add Picture (Picture in the dialog editor controls palette) static controls to your dialog for the bitmaps and then add static controls next to them for the labels.
If you're using the .NET WaveformGraph or ScatterGraph, there is a .NET Legend control that will let you add legend items for any plots or cursors that you would like to display in the legend.
- Elton