OL2007, VSTO C#.

I have a 355 pixel wide form region for the main Outlook window that sits
below the Email Body preview pane.

When the user enlarges the Email Body preview pane more than 355 pixels wide
(e.g. to 700), there is a lot of white blank space to the right of the form
region. Is there any way I can align the whole form region to the right? So
far it only aligns left.