Passing an TAdoDataset as parameter using TADOStoredProc

Question

i have an oracle stored procedure with 2 parameters declarated as input cursors. how i can assign this parameters using the TADOStoredProc component?

when try to assign the TADODataSet to the parameter can't compile the code because the ide gives me this error.

incompatible types : OleVariant and TAdoDataset.

ORACLE

PROCEDURE MYSTOREDPROCEDURE(P_HEADER IN TCursor, P_DETAL IN TCursor, P_RESULT OUT VARCHAR2)     
BEGIN
//My code goes here


END;

Delphi

function TMyClass.Add(Header, Detail: TADODataSet;var _Result: string): boolean;
Var
  StoredProc : TADOStoredProc;
begin
  Result:=False;
    StoredProc:=TADOStoredProc.Create(nil);
  try
    StoredProc.Connection   :=ADOConnection1;
    StoredProc.ProcedureName:='MYSTOREDPROCEDURE';
    StoredProc.Parameters.Refresh;
    StoredProc.Parameters.ParamByName('P_HEADER').Value    :=Header;//How can assign this parameter?
    try
     StoredProc.Open;
     _Result:=VarToStrNull(StoredProc.Parameters.ParamByName('P_RESULT').Value);
     StoredProc.Close;
     Result:=True;
    except on E : Exception do
      begin
       _Result:=E.Message;
       //exit;
      end;
    end;
  finally
    StoredProc.Free;
  end;
end;

UPDATE

i tried this option too, without luck.

StoredProc.Parameters.CreateParameter('P_HEADER',ftCursor,pdInput,1,Header);