Hi,
you could create a new Date instance in your smooks configuration and then referens it in the fileNamePattern element.
For example:
<smooks-resource-list>
<jb:bean beanId="myDate" createOnElement="order-item"/>
...
<file:outputStream resourceName="orderItemSplitStream" openOnElement="order-item">
<file:fileNamePattern>order-${order.orderItem.itemId}-${myDate?date}.xml</file:fileNamePattern>
...
</smooks-resource-list>
The format that Freemarker uses, above specified as '?date', can be configured. You can find more information about the formatting here
Regards,
/Daniel