Get Bitmap / PNG with document Manager

Hi all.

Does anyone know how to use the

SwDMDocument10::GetPreviewBitmap and
SwDMDocument10::GetPreviewPNGBitmap

methods that are available with the Document manager?

I would like to use these to populate a picturebox.Image propertyin VB.Net Express 2008, but the returned value on these methods arenot 'image' objects... just 'Object'

How can I use these methods to populate a picturebox?

RegardsSolidworksApi macros