You need to deploy it as an XMBean. Look for example in the standard conf/jboss-service.xml for mbean deployed as xmbean, and in conf/xmdesc for their descriptors.
Read the 2nd chapter of the server documentation.
see also http://wiki.jboss.org/wiki/Wiki.jsp?page=HowDoIXMBeanIzeAnExistingStandardMBean
Perfect, works fine.. the way I wanted.
Thanks for the prompt response.