I'm using a Calculated Cell formula with the following Calculation
Value:

Sum({[Period].CurrentMember} as PeriodSet,
Sum(Filter({([Period].[Months].Members.Item(0):[Período].CurrentMember)},
([Schedule].[Amount of Payments])>
(Rank(PeriodSet.Item(0),{[Period].[Months].Members}) -
Rank([Period].CurrentMember,{[Period].[Months].Members}))
),
[Schedule].[Monthly Cost]))

wich is more described in the following article in this group:

http://groups.google.com/groups?hl=p...com%26rnum%3D2

it works fine but when I write it through the Analysis Manager, in the
Cube Editor, the MDX Builder can't parse it correctly, I get the
message:
"Fomula error – syntax error – token is not valid:"
({[Period].CurrentMember} as ^PeriodSet^, … ", meaning that the MDX
Builder can't understand the alias set.

The only way that I could create the formula was using an ADOMD cube
command.

I'm using AS SP3A with hotfix 820. Does anybody know how I can fix it
and to use the MDX Builder?