YTD calculation

[reacha]

I am creating a measure in the universe as current YTD.

I have created the Individual month measures for 2011 and 2012.
like there are two folders 2011 and 2012 and in that they are month measures from jan to dec.

2011
-----
JAN-11,FEB-11,MAR-11,APR-11,MAY-11,JUN-11,JUL-11,AUG-11,SEP-11,OCT-11,NOV-11,DEC-11

2012
----
JAN-12,FEB-12,MAR-12,APR-12,MAY-12,JUN-12,JUL-12,AUG-12,SEP-12,OCT-12,NOV-12,DEC-12

now when i try to calculate the current YTD as JAN-11+FEB-11+MAR-11+APR-11..

i don't know what happens when the year changes that is in next jan(how can i change that to look for measures of 2012)


and there are 3 items like bal,con,ft

Current YTD
------------------
case when item = bal then jan-11*31+feb-11*28+-------------+oct-11*31/(31+28---+31)
when item = con then jan-11+feb-11+----------+oct-11
when item = ft then oct-11
end

Please help me out!!

Thanks,
reacha