Hi Bill -
More context. I have 2 VSTO applications. One is an Excel Add-In, the other is an Excel workbook project, with a task pane.
Ideally what I'd like to have happen is the user installs the add-in, opens excel, and from my add-in ribbon, they are able to open the workbook referenced in my workbook project, which would have the task pane.
VSTO has an easy open workbook method, but that won't work on a VSTO workbook project.