Force formula re-calculation on file open from Excel

[zymon]

Hello,
I desperately need support for forcing excel to re-calculate the formulas on open.

This is following part:
<x:calcPr calcId="999999" fullCalcOnLoad="1"/>

Can you give me some clues where to add it, so I could contribute and add this functionality.

[guyonroche]

Added in v3.3.0