If more than just a single pattern is required to specify the databases to merge, it cannot be done with the current implementation of the plugin.

It would be better to change the following code in the clover:merge goal from:

<ant:cloverDbSet dir="${_multiproject_basedir}">
<ant:include name="${maven.clover.merge.databases}"/>
</ant:cloverDbSet>

to:

<ant:cloverDbSet dir="${_multiproject_basedir}" includes="${maven.clover.merge.databases}"/>

The 'includes' attribute on cloverDbSet provides everything that the 'include' tag provides, with the added benefit of being able to use multiple patterns and files.