FM - Navigation with dimensional function

[giovanni.lucarelli]

Hi to everybody!

Please I need help!!!!!!!

I have a parameter ?par_MONTH? on my time dimension (it's a hierarchy) on Month and for example it has values as "2008-April"; (this is the business key and member caption of the level);

then i create a new query item: [Data Mart XXXX].[Dossier Date].[Dossier Date].[Month]->?par_MONTH?
that i name [Selected Period];

then i create another query item: periodsToDate([Data Mart XXXX].[Dossier Date].[Dossier Date].[Year],[Selected Period]) and I want to retrieve 2008-January to 2008-April... but this function is totally unsane!!!!

maybe I need to order my hierarchy? how can i do this?

please help me and sorry for my english