Visio Professional Timeline Format question

[ConfusedJosh]

When creating a Gantt chart I am unable to change the timeline format mm/dd format.  Currently the Date Time units is set to Major Units (Month) and Minor Units (Week) but there doesn't seem to be a way to change the displayed date format for the minor units.  This is the minor date format (in weeks) displayed horizontally

[wapperdude]

There is no means to change the formatting of the displayed values.  Everything is exclusively controlled by the Gantt chart add-on. 

Wapperdude