Has anyone tried out to execute Oracle Spatial functions via ADO?

I'm using Oracle 8i and I want to execute an SQL statement with geometry
areas as result:

SELECT ID,sdo_geom.sdo_area(base.SDOGEOMETRY,meta.diminfo ) AS SDOArea
WHERE meta.table_name=MyTable' AND meta.column_name='SDOGEOMETRY'

This statement is executed correctly in Oracle Worksheet, but if I execute
the statement via ADO (that works!) and, then, read out the number of
datasets with RecordCount, I get the error message:

ORA-13050: Unable to construct spatial object
ORA-06512: at "MDSYS.SDO_3GL", line 399
ORA-06512: at "MDSYS.SDO_GEOM", line 3441
ORA-06512 at line 1

The interesting point of view is, that the recordset object is able to
define correct field objects (the field types are ok!), but as soon as I try
to address the datasets (with RecordCount or navigation methods like
MoveNext), an error is raised.

What can I do to calculate areas via ADO?