Aggregatting tables -> who succeed??

Hi everybody!
I'm trying to do aggregating tables. This is my xml definition schema for Aggregates:

<AggName name="JFSV_T_ACTIVITY_MONTH" approxRowCount="44660" ignorecase="true">
<AggMeasure column="SCHEMADBA-&#62;JFSV_T_ACTIVITY_MONTH-&#62;NUM_ACTS" name="[Measures].[Num Acts]"></AggMeasure>
<AggLevel column="SCHEMADBA-&#62;JFSV_T_ACTIVITY_MONTH-&#62;MES_INI" name="[Tiempo].[Time per day].[Month]" collapsed="false"></AggLevel>
</AggName>

Where in column attributes there is:
SCHEMADBA-&#62;JFSV_T_ACTIVITY_MONTH-&#62;AGG_ROW: that's the column AGG_ROW in the table JFSV_T_ACTIVIDAD_MONTH in the oracle schema SCHEMADBA.

The fact table is something like three columns: Act, month and day. And the aggregation table is like: act and month.

I did this xml almost atomatically using the Schema Workbenc application, it guides you in every point!

The fact is when I do the MDX, the result SQL is pointing to the fact table instead of the aggregate table.

Somebody succeed trying to aggregate? Do I need to use the Pentaho Aggregation Designer? Can't create the xml by my own?

Thanks a lot!!