It doesn't seem to me that the Task Pane is much like any other command bar.
I think it's classified as a command bar in the Office object model just for
convenience. About the only customizing I've been able to do with it is to
add files to the New Workbook pane via the NewFile object.

Sub AddToTaskPane()
Dim x As NewFile
CommandBars("Task Pane").Visible = False
Set x = Application.NewWorkbook
x.Add "c:\bookNew.xls", msoNew
'Next to refresh, else changes do not appear
CommandBars("Task Pane").Visible = True
End Sub

Sub RemoveFromTaskPane()
Dim x As NewFile
CommandBars("Task Pane").Visible = False
Set x = Application.NewWorkbook
x.Remove "c:\bookNew.xls", msoNew
CommandBars("Task Pane").Visible = True
End Sub

--
Jim Rech
Excel MVP