When setting "Indent mode" on the "Style" tab of the pivot chart, "Show partial sums" on the "Presentation" tab becomes grayed-out, so be careful. It took me a while (trial and error approach) until I fount out the connection.
So, if you're not gettinng totals on the pivot chart and the "Show partial sums" option is gryed-out, check "Indent mode" on the "Style" tab!
Cheers,
Marko