Tricky Problem. Date and Time Modification

[patrick kilgore]

I'm trying to modify the date at the footer of a powerpoint presentation programatically to swap out the dynamically generated date with my own date, but there doesn't seem to be an easy way to do this.

Here's what I've tried.

-finding a text range in the relevant shape objects
-changing the DateAndTime.Text in:
--SlideMaster.HeadersFooters
--NotesMaster.HeadersFooters
--TitleMaster.HeadersFooters
--slide.Master.HeadersFooters
--slide.HeadersFooters.Footer
(which changes the date, but also erases other text that might be in the shape)