Sorry for my late reply - I was in vacation and is recently back.
Attached please find an attached drawing and see if that satisfies your need.
I did not use Endcap Edit in-place but Cleanup Edit in-place (a new functionality introduced in AutoCAD Architecture 2010). The former one is used at a single wall end condition, and the later one is used at a wall cleanup condition (For example, the joint where two walls are connected). You can access the function by selecting walls forming the wall joint you want to edit, and click the button Cleanup Edit in Place from the Ribbon. Alternatively, you can enter command WALLCLEANUPEDIT, select the walls forming the wall joint, press Enter to enter Edit in-place mode. Once you are in Edit in-place mode (similar to Endcap Edit in-place mode) you can edit the component directly via the component grips or using provided tools to achieve the result you need. Personally I find Cleanup Edit in-place most useful when the layout of the walls are finished and there will be none to little modification to that wall joint being edited.
Hope this helps.
Thanks,
Sam