CustomFieldValue customFieldValue = new CustomFieldValue();
customFieldValue.setCustomFieldId(customFieldId);
customFieldValue.setValue(textValue);
customFieldValues.add(customFieldValue);
DropDownCustomFieldValue dropDownCustomFieldValue = new DropDownCustomFieldValue();
dropDownCustomFieldValue.setCustomFieldId(dropDownCustomFieldId);
dropDownCustomFieldValue.setCustomFieldOptionId(customFieldOptionId);
customFieldValues.add(dropDownCustomFieldValue);
// Only add existing custom field values for different custom fields than
// the ones you are setting.
if (lineItem.getCustomFieldValues() != null) {