I think you can stick to exec:exec, using that kind of configuration if you want to give the project classpath to the Java process you use:
<plugin>
<groupId>org.codehaus.mojo</groupId>
<artifactId>exec-maven-plugin</artifactId>
<configuration>
<executable>java</executable>
<longClasspath>true</longClasspath>
<arguments>
<argument>-XX:MaxPermSize=128M</argument>
<argument>-Xmx1024M</argument>
<argument>-Xdebug</argument>
<argument>-Xrunjdwp:transport=dt_socket,address=8888,server=y,suspend=n</argument>
<argument>-classpath</argument>
<classpath/>
</arguments>
</configuration>
</plugin>
See also the plugin Usage page