How to filter using calculated date value based on parameter in MDX - sharepoint

Question

I'm trying to fetch the values based on a Date value passed as parameter (named AsOnDate) into a Performance Point report's MDX from a Webpart Date Filter. It's an Accounts database and the scenario is to fetch the Dormant accounts data. The problem I'm facing is that I need to fetch the Accounts having Dormant Date till 6 months before the AsOnDate value, i.e. AsOnDate -6 months, I managed to calculate the 6 month old date using DateAdd() function, like following:
DateAdd('m', -6, DateValue('<<AsOnDate>>'))
Now, I cann't figure out how to pass this value in place of the paramter in WHERE clause, MDX query looks like:
WITH
SET [Products] AS { <<Product>> }
MEMBER [Measures].[Dormant A/C Count] AS ([Measures].[Account Head Count])
MEMBER [Measures].[Dormant A/C Vol.] AS ([Measures].[LC Balance])
MEMBER [AH].[Subhead - Description].[Totals] AS Aggregate([Products])
SELECT
{ [Measures].[Dormant A/C Count], [Measures].[Dormant A/C Vol.]}
ON COLUMNS,
{[Products], [AH].[Subhead - Description].[Totals]}
ON ROWS
FROM
[MyCUbe]
WHERE (
[AH].[Is Dormant].&[1],
[AH].[Is Inoperative].&[0],
{NULL : [AH].[Dormant Date].&[ DateAdd('m', -6, DateValue('<<AsOnDate>>')) ]}
)
I get this error:
Error running data source query.
The 'DateAdd('m', -6, DateValue('2012-12-03'))'
string cannot be converted to the date type.
I have tried StrToMember() like:
WHERE (
[AH].[Is Dormant].&[1], [AH].[Is Inoperative].&[0],
{ NULL : StrToMember("[AH].[Dormant Date].&["+DateAdd('m', -6, DateValue('<<AsOnDate>>'))+"]")}
)
However, passing the Date Filter value directly as following works fine:
WHERE ( [AH].[Is Dormant].&[1], [AH].[Is Inoperative].&[0],
{ NULL : [AH].[Dormant Date].&[<<AsOnDate>>T00:00:00]} )

Answer 1

Figured it out, after some hit n trials.. managed to hack a combination of StrToMember() and Format() to convert calculated Date into string and feed it into MDX as Member, here's the working WHERE clause:
WHERE ( [AH].[Is Dormant].&[1], [AH].[Is Inoperative].&[0],
{ NULL : StrToMember("[AH].[Dormant Date].&[" + Format(DateAdd('m', -6, DateValue('<<AsOnDate>>')), 'yyyy-MM-dd') + "T00:00:00]") } )
Hope it will prove helpful for someone out there..