How do I create an Extended Item Desription ??

soLine.InvokeMethod("nAddLine");
soLine.InvokeMethod("nSetValue", "ItemCode$", "NEW IMM");
soLine.InvokeMethod("nSetValue", "QuantityOrdered", qty_p);
// DESCRIPTION
object[] getIDesc = new object[] { "ItemCodeDesc$", "" };
soLine.InvokeMethodByRef("nGetvalue", getIDesc);
//oExtendedDescriptionBusiness

object[] getIDesExt = new object[] { "ExtendedDescritpionKey$", "" };
soLine.InvokeMethodByRef("nGetvalue", getIDesExt);

string key = getIDesExt[1].ToString();

using (DispatchObject extDesc = new DispatchObject( soLine.GetProperty("oExtendedDescriptionBusiness")))
{


string nesxKey = extDesc.InvokeMethod("sGetNextExtendedDescriptionKey").ToString();
extDesc.InvokeMethod("nSetKey", nesxKey );
extDesc.InvokeMethod("nSetValue", "ExtendedDescriptionText$", "test desc");
extDesc.InvokeMethod("nSetValue", "CreationModuleCode$", "S/O");
extDesc.InvokeMethod("nWrite");

}

soLine.InvokeMethod("nWrite");


}
ordeR.InvokeMethod("nWrite");