I'm looking for some advice from anyone who has experience writing addons for PowerPoint on both Windows and Mac machines.

We have a Windows Office 2007 addon (.NET) that we'd like to port to the Mac.

Thus, in PowerPoint 2008 for the Mac, we require the following functionality:

Ribbon/Fluent extensibility
Custom Task Panes
Read/write custom document properties
Save slides as images
Read text and shape information from slides
Get notification of the following PowerPoint application events; SlideSelectionChanged, PresentationClose and AfterPresentationOpen.
I am hoping someone with experience writing Office addons for Windows and Mac, can advise.

Thanks