Template Query Modification

Hello Collections Experts,

Can anybody pls advise on how to:
1. Deactivate current Query and Template assignment? There is no End-Date neither Active flag available under the "Manage Templates Query" form.
2. We need to modify the standard Query by adding a new header level field - "VAT number". That we did under the main xml COLLECTION part of the Query. However, this new field is still not appearing in the dynamically generated XML stream - not available in the XMLDATA field of the IEX_XML_REQUEST_HISTORIES table.
Are there some restrictions on the fields added on the header level? Do we need to run any synchronization process?