Im having a problem getting my head arou

Im having a problem getting my head around some MDX. I have managed to create my YTD value using: SUM(YTD([Calendar].[Year - Period - Date].CurrentMember), [Measures].[Sales Value]) I have my last year YTD value with: SUM(YTD(ParallelPeriod([Calendar].[Year - Period - Date].[Year] , 1 , [Calendar].[Year - Period - Date].CurrentMember)) , [Measures].[Sales Value] ) However I need to create a Full Last Year Value. (which is the same as the Last Year YTD value if it were run on the 31st Dec), basically the full value of the year. I have SUM([Calendar].[Year].currentmember.prevmember, [Measures].[Sales Value]) but this only displays the correct value against the year or date level but not on the period (Probably as a period looks like [02 2010] etc. my date heirachy is [Year] - [Period] - [Date] Does anyone have any idea of what I can do to get it on the Period Level? thanks. Andrew