Just run
mvn clean install
Generated jar inside impex-generator-distribution/target should contain all code base - rest dependencies is right from 'platform'
If you would like to embedded this ant task in your script, here is the sample snippet.
<typedef name="impexGen" classname="xxx.platform.impexgen.velocity.ant.GenerateLocalizedImpexesTask" onerror="report">
<classpath>
<fileset dir="${ext.extension.path}/lib">
<include name="impex-generator-distribution-1.0-SNAPSHOT.jar"/>
</fileset>
<fileset dir="${ext.core.path}/lib">
<include name="*.jar"/>
</fileset>
<fileset dir="${platformhome}/bootstrap/bin/">
<include name="*.jar"/>
</fileset>
<fileset dir="${platformhome}/lib">
<include name="*.jar"/>
</fileset>
<fileset dir="${ant.home}/lib">
<include name="ant*.jar"/>
</fileset>
</classpath>
</typedef>