1) In the Preferences:Providers menu, create a group [mine is named JBoss 4].
2) Right click on the group you have created, and add the following jar: jboss-messaging-client.jar. This will include all of the classes you need. You will find it in the zip file contained in the download of JBoss Messaging 1.0.1RC4.
3) Click "Dont Scan"
4) Under "contexts", right click and click "New->New Context". Below is the information I used for my setup.
Change the loader to your group name you setup in step 1.
loader == JBoss 4
providerURL == jnp://localhost:1099
initialContextFactory == org.jnp.interfaces.NamingContextFactory
urlPkgPrefixes == org.jnp.interfaces:javax.jnp
securityCredentials == admin
securityPrincipal == admin
The other settings in my setup are blank.