get cell renderer with XDE ?

I would like get the cell renderer in a JTable with rational XDE but it
seems be impossible.

My code :

TestObject
bj2=(TestObject)table.invoke("getCellRenderer","(II)Ljavax/swing/table/Table
CellRenderer;",params);
params=new Object[6];
params[0]=table;
params[1]=null;
params[2]=new Boolean(false);
params[3]=new Boolean(false);
params[4]=new Integer(0);
params[5]=new Integer(0);
TestObject
obj3=(TestObject)obj2.invoke("getTableCellRendererComponent","(Ljavax/swing/
JTable;Ljava/lang/Object;ZZII)Ljava/awt/Component;",params);

Exception :
com.rational.test.ft.BadArgumentException: Test Objects passed to the
Software Under Test must be registered references.

Someone can help me???

thx

Thx for your help...
I resolve the problem by implementing a method in my JTable class which
calls getTableCellRendererComponent method of the Cell Renderer class.