java – Eclipse BIRT : how to define datamatrix element in xml file

how to define a barcodetype as square in xml file in Eclipse BIRT ?

                                    <extended-item extensionName="BarcodeItem" id="978">
                                    <property name="marginBottom">1pt</property>
                                    <property name="marginRight">50px</property>
                                    <property name="height">25px</property>
                                     <property name="barcodeType" type="constant">DATA_MATRIX</property>
                                    <property name="barcodeAngle" type="constant">0</property>
                                    <property name="encoding" type="constant">ISO-8859-1</property>
                                     <property name="X" type="constant">2</property>
                                    <property name="content" type="javascript">row["matriceTessi"]</property>
                                </extended-item>