I know i'm REALLY late to the discussion, but I just started down the same road this morning.
I went into controls, and at the very bottom, there's "Add or Remove Custom Controls". Then, if I choose the ActiveX control, there are two options which may help:
1. Microsoft Office Chart 11.0
2. Microsoft Office Spreadsheet 11.0
Although I can't figure out how to get it to save the user's inputted data after a submit. Nonetheless, I posted this just in case others were to follow with the same question.