I'll keep it short:

YTD([Date].[Day].[20110902]) works. It returns a set of dates from the beginning of 2011 until today.

YTD(CurrentDateMember([Date.Calendar], "[""Date""]\.[""Day""]\.[yyyymmdd]")) gives out a curious NullPointerException error, not quite sure what actually went wrong.

Note: CurrentDateMember([Date.Calendar], "[""Date""]\.[""Day""]\.[yyyymmdd]") alone works and returns the expected Member of the [Date.Calendar] hierarchy.

Any ideas?