How do I get the YTD AdCost column shown on the right in the sample output from my Project cube?


Fiscal____Fiscal__Fiscal____Fiscal___AdCost_______ ___YTD_AdCost
Decade___Yr_____Yr-Q____Yr-Mo
__________________________________________________ ________
2000_____2005 2005-Q1_2005-01 8,795,243.85______8,795,243.85
________________________2005-02 6,317,225_________15,112,468.85
________________________2005-03 103,213,925.1_____etc.
________________2005-Q2_2005-04 97,310,859.5
________________________2005-05 117,331,518.5
________________________2005-06 82,267,315
________________2005-Q3 2005-07 38,666,890
________________________2005-08 42,250,000
________________________2005-09 25,117,000
________________2005-Q4 2005-10 13,517,000
________________________2005-11 22,777,543

1) I need a YTD colum that sums AdCost from the same year.
I have other members in the source dimension table including month (01,02,...).

I'd like to allow users to use this column in the cube spreadsheet.

2) Not sure whether to use a calc member (seems easier to write) or calculated cell.

Note that this is a home-grown time dimension not from AS2k.