Calc HYPGEOMDIST: conditionally changing function opcode when saving to Excel format

Hi Eike,

ODFF1.2 has a HYPGEOMDIST function with 4 mandatory and an optional 5th argument (cumulative), 
Excel has a HYPGEOMDIST with 4 mandatory arguments and a HYPGEOM.DIST with 5 mandatory arguments.
All 3 are the same (apart from (non)cumulative calculation).

To fix tdf102498, and to simplify the current code, I want to use one 
ScInterpreter::ScHypGeomDist() function for all, and
-save in ODF as HYPGEOMDIST;
-save in Excel as HYPGEOMDIST in case of 4 arguments and HYPGEOM.DIST in case of 5 arguments.
That means I have to change the opcode ocHypGeomDist to ocHypGeomDist_MS when saving to Excel 
format.

I remember that this can be done somewhere, but I forgot in which source file/function that is to 
take place.
Do you know or have a hint?

Winfried