Since I use the add-in, I'm not that familiar with the actual code for this.

How familiar are you with Excel's object model? http://msdn.microsoft.com/en-us/libr...ice.14%29.aspx It seems to me that the code should not be overly difficult. Simply assign the appropriate "formula" string (eg "=sheet1!A1") to the formula property of each datalabel object (eg chart(1).seriescollection(1).datalabels(1).formula="=sheet1!A1"). Put all of that inside of a For...Next/For Each...Next loop (are you familiar with For..Next loops?).

I know I have seen others post similar code for this before. I know that it can be a challenge to wade through search results, but you might try and see if you can find previously posted code.