If the holiday vector in NETWORKDAYS(start,end,holiday_vector) contains any
"null" strings (i.e. they've had the value "" inserted), then NETWORKDAYS()
returns #VALUE!

Any ideas how to get around this? I do need to have the empty cells - the
vector can be used for different countries, with different numbers of
holidays. And I can't use zero as the empty filler, since 0 actually
represents a valid date.

I'm converting from OpenOffice's spreadsheet which doesn't have the same
problem.

tia.
rmtp