Use horizontal lookup with pivot table

hello,

I set up a graph that contains one series from a given range and two series
from a pivot table.

The data is filtered by the pivot table by month (1 to 12) and by type
(Development/Infrastructure). If there is nothing in a given moth you end up
with less than 12 points to plot for a given year.

To plot this I use another range using hlookup to have the data in the
corresponding month of the year.

The problem comes when I need to update the pivot table. The range used in
the hlookup formula has to be updated asweel and I don't know if there is
something to tell hlookup that the array is the pivot table and not a fixed
range.

Any help will be greatly appreciated.

Thank you, regards