Hello Bert,
the metadata.xml does not contain the annotation information, because the annotation information is delivered in an own annotation file via a service call (e.g. "/sap/opu/odata/IWFND/CATALOGSERVICE;v=2/Annotations(TechnicalName='<technical name of annotation service>',Version='<version of annotation service>')/$value/".
The UI.lineItem and UI.selectionField annotation are ok, but the @Search.* annotations are not released yet for customer usage (check note in Search Annotations - Reference - SAP Library).
Best Regards,
Florian