I finally found an answer.
So I needed to generate excel reports with a lot of pivot charts linked to a main table.
But using a table was a bad idea. Instead, the pivot charts must be linked to a named range.
The last thing to know is that the error message "Invalid References" appears if the named range doesn't use the OFFSET function.
My named range formula is :
=OFFSET(Sheet!$A$1, 0, 0, COUNTA(Sheet!$A:$A), NUMBER_OF_COLUMNS)
Where Sheet is the name of the worksheet and NUMBER_OF_COLUMNS is the number of columns of the data.
That's it. I can now generate excel report without any line of code, only using SSIS 2005.