I'm using Office 2010 (14.0). It doesn't have Button. It does have Ribbon I found the following Options>Customise the Ribbon>Choose Commands> Edit Links to Files moved into new Custom Group. I felt pleased with myself at having found how to make it available.
However my joy was shortlived. I highlighted a diagram I'd imported only to find that Edit Links to Files was greyed out.
I tried Alt-E, k and Shift-F9. None worked. I guess I'll have to use pencil and paper to make a note where the figures came from.
Thanks for trying