Thanks for all the help I got here, but I'm still stuck with the following problems : I can't have both the JVM metrics and the managed Spring metrics at the same time in AMS (cf http://forum.springsource.org/showthread.php?t=79454 for the full thread).
It seems that when JMX remote is activated, Spring exports its metrics in the wrong MBean Server. It may be the way I plugged Spring in the JMX MBean server... this is my configuration :
<bean id="mbeanServer" class="org.jboss.mx.util.MBeanServerLocator" factory-method="locateJBoss" />
<bean id="exporter" class="org.springframework.jmx.export.MBeanExporter">
<property name="autodetect" value="true" />
<property name="server" ref="mbeanServer" />