How can I get an SLSB to log in to an queue.

If it was an MDB I would do it like this:

 <message-driven>
 <ejb-name>CMyMessageBean</ejb-name>
 <destination-jndi-name>queue/myQueue</destination-jndi-name>
 <mdb-user>scott</mdb-user>
 <mdb-passwd>tiger</mdb-passwd>
 <resource-ref>
 <res-ref-name>jdbc/base</res-ref-name>
 <jndi-name>java:/jdbc/myconnection</jndi-name>
 </resource-ref>
 </message-driven>