Assuming that you have the ACA.cuix loaded as your main customization, in the upper left pane of the Customize User Interface dialog, expand the following nodes: ACA > Ribbon > Panels > Annotate - Scheduling - ACA > Row 1 > Sub-Panel 2 > Row 1 > Door and then select the Door Schedule node.
On the right side of the dialog, in the Properties pane, under the Command category, find the Macro parameter. For the Door Schedule tool, it is
Code:
^C^C_AecRibbonTool Door Schedule - ribbon;
This is what gets executed when you select the button. THe AecRibbonTool command takes one piece of input, which needs to be the name of a tool palette tool that is loaded into the current workspace in order to work. Any ACA style-based tools on the ribbon use this command to execute a tool palette tool, as if you had selected the tool palette tool directly.
In order to create ribbon tools that create ACA Schedule Tables (or other style- or definition-based AEC Content), you will first need a tool palette tool, and then you would use the AecRibbonTool command to reference it. More detailed information about the process can be found in this Tech Talk article on the AU website, published in December, 2009.