Could anyone please give me some advice on the problems when applying
conditional format on 'ctrl+shift+enter' CSE formulas cells using excel 2007?

The raw data is simply in 3 columns,
A B C
x-axis y-axis data
.... ... ...

My task is to plot the map of data according to its x-y axis values, and my
method is to use
{=IFERROR(INDEX('x.xls'!data,MATCH(1,('x.xls'!Col= x)*('x.xls'!Row=y),0)),"")}
all over the map. They all work very well.

The next step is to change the background color on the map based on the
value. However, the conditional formatting does not works on CSE formulas,
which has no response at all. I tried replace the formulas by the value of
data, it works perfectly. So, the problem is conditional formatting does not
recognize the value of CSE formulas. Is that right?

Could you please give me any idea how I could resolve this issue? PS: I do
not want use VBA macros. Thank you very much.