source code is not linked to dependencies with a classifier

Using the latest copy of the plugin from SVN, it correctly downloads and links source code (and javadocs) to dependencies defined in the POM. This does not happen, however, to dependencies with a classifier.

To reproduce, add a dependency with a classifier, like this:
<dependency>
<groupId>...</groupId>
<artifactId>...</artifactId>
<version>...</version>
<classifier>tests</classifier>
</dependency>