calculated field - TDecisionQuery

Did anyone ever add a calculated Field to the DescicionQuery, and use it
the DecisionGrid ?

When I add a calculated field to the *.pas file and to the *.dfm file, I
dont' see it in the
Decision Query Editor (so I can't add the field to dimensions/summaries)
and unfortunately it's the only field I can see in the Decision Cube
Editor/available fields.

Anyone know what I have to do to see my calculated field in Decision
Query Editor ?
Anyone you know what I have to do to see my other fields in Decision
Editor ?