Ok, I partly resolved this way that should works with some limitations:
<plugin>
<artifactId>maven-antrun-plugin</artifactId>
<version>1.6</version>
<dependencies>
<dependency>
<groupId>ant-contrib</groupId>
<artifactId>ant-contrib</artifactId>
<version>1.0b3</version>
<exclusions>
<exclusion>
<groupId>ant</groupId>
<artifactId>ant</artifactId>
</exclusion>
</exclusions>
</dependency>
<dependency>
<groupId>ant</groupId>
<artifactId>ant-nodeps</artifactId>
<version>1.6.5</version>
</dependency>
</dependencies>
<executions>
<execution>
<phase>package</phase>
<id>copy-resources</id>
<configuration>
<exportAntProperties>true</exportAntProperties>
<tasks>
<!-- add the ant tasks from ant-contrib -->
<taskdef resource="net/sf/antcontrib/antlib.xml" classpathref="maven.plugin.classpath"/>
<var name="import.set" value=""/>
<for param="file">
<path>
<fileset dir="${project.build.directory}" includes="*.jar"/>
</path>
<sequential>
<var name="basename" unset="true"/>
<basename file="@{file}" property="basename"/>
<var name="filenames" value="${basename}"/>
<var name="import.clause" value='<IMPORT MODULE="${filenames}" NAME="${filenames}" REQUIRED="true"/>'/>
<var name="import.set" value="${import.clause}${line.separator}${import.set}" />
</sequential>
</for>
<property name="import.jar" value="${import.set}"/>
<echo>${import.jar}</echo>
</tasks>
</configuration>
<goals>
<goal>run</goal>
</goals>
</execution>
</executions>
</plugin>
Still some problems: even if exportAntProperties is set to true, the property ${import.jar} is still not available outside ant taska in other maven goals, while if i switch to maven-antrun-plugin 1.7 version, a "Error executing ant tasks: org.apache.tools.ant.launch.Locator.fromJarURI(Ljava/lang/String;)Ljava/lang/String;" exception is thrown. Still no clues...