Forget the built in custom types. It's better to build your own. Create your
chart using all the data, to produce a chart with three line series all on
the primary axis. Select the Volume series, and on the Chart menu, use Chart
Type to change it to a column type. Then double click on the Volume series,
and on the Axis tab, choose Secondary.
Jon Peltier, Microsoft Excel MVP
Peltier Technical Services
Tutorials and Custom Solutions