How to prevent Line in the Line/Bar Chart from connecting points when not appropriate

Please refer to the Oracle publication, "Oracle CRM On Demand Reporting" by Michael D. Lairson ISBN# 978-0-07-159304-5 dated 2009.

On page 316 of the above publication is figure 11-43 showing a multichart report.  The bottom chat is a Line/Bar Combo.  There are two fields displayed in the chart (closed revenue and potential revenue).  Closed Revenue is the Line.  Closed Revenue does not connect completely across the report.  There are two instances where Closed Revenue is absent.  How does one create a chart in Oracle CRM on demand where the line in the Line/Bar Combo does not connect all of the way across the chart?  It is obvious in figure 11-43 that some values of Closed Revenue are zero and