when using, seam all my entities are annotated

in the eclipse ide, to use the hibernate plugin, I need to map all entities in the hibernate.cfg.xml file:

<mapping class="com.mydomain.web.entity.WebUser"/>
<mapping class="com.mydomain.web.entity.Category"/>

i find it quite awkward to enter all classes in this file manually.
so, does anyone know a way to relieve me of this burden?
e.g. to let seam create those mappings automatically?