I struggled with the same question. It was a simple matter to just make my own child component for this requirement using the +2nd light as the starter dwg for the symbol and adding the connection points. Rather than overwriting the dwg file I created a new one just in case someone would eventualy explain the intended usage of the +2nd light block. Though idealy, it makes no sense showing an electric lamp on a schematic without any wire connections. The only other available selection within the default symbol library I found was the pilot lights, but they are not child components. This doesn't work well with some manufacturer part numbers that sell illuminated push buttons as an assembly.
Ronald Michaud
Electrical Engineer
Darly Custom Technology Inc.
www.darlytech.com
Via Lite V3 thru ACADE 2011