how use IncludedMembers to filter multi-level dimension

[Frank]

I have a Date dimension with three levels, and would like to include
only one date, say, (year,month,day)=(2004,12,1), how can do that?
I tried following code, couldn't make it work.
FilterAxis.FieldSets("Date").Fields("year").IncludedMembers ="2004";
FilterAxis.FieldSets("Date").Fields("month").IncludedMembers ="12";
FilterAxis.FieldSets("Date").Fields("day").IncludedMembers ="1";

Thanks in Advance