Orbeon Alfresco Integration and workflow-send

Hi,
I wrote my form and configured Orbeon integration to integrate it with Alfresco.
The documentation says I need to submit the form with the workflow-send button but I can't find how to use it.

when I wrote:
<fr:workflow-send-button submission="save-submission">
                <xf:label>Save</xf:label>
</fr:workflow-send-button>

No button appears in the form.