While testing bug 506698, I found following behavior:

Only 1.3 (QMFv2 capable) broker was used in testing.

1.3 QMF console was able to see all the agents when asked
for schema, but QMFv1 sesame agent objects can not be seen using
"list sysimage" without running 1.2 qpid-tool first.

Despite my original suspicion, this bug is indifferent
to the version of RHEL.

RHEL4
  MRG 1.2 packages:
    amqp-1.0.750054-1.el4
    python-qpid-0.5.760500-6.el4
    qmf-0.5.752581-34.el4
    qpidc-0.5.752581-34.el4
    sesame-0.4.3153-2.el4
  MRG 1.3 packages (installed on different host):
    python-qmf-0.7.946106-13.el4
    python-qpid-0.7.946106-14.el4
    qmf-0.7.946106-17.el4
    qpid-cpp-client-0.7.946106-17.el4
    qpid-cpp-server-0.7.946106-17.el4
    qpid-tools-0.7.946106-11.el4

RHEL5
  MRG 1.2 packages:
    amqp-1.0.750054-1.el5
    python-qpid-0.5.752581-4.el5
    qmf-0.5.752581-34.el5
    qpidc-0.5.752581-34.el5
    sesame-0.4.3153-2.el5
  MRG 1.3 packages (installed on different host):
    python-qmf-0.7.946106-13.el5
    python-qpid-0.7.946106-14.el5
    qmf-0.7.946106-17.el5
    qpid-cpp-server-0.7.946106-17.el5
    qpid-cpp-client-0.7.946106-17.el5
    qpid-tools-0.7.946106-11.el5


How reproducible: 90%
  (sometimes, using the same steps, I can list the objects)

Steps to Reproduce:
1. First you have to be running a MRG 1.3 broker where no but
   one QMF1 agent connects (e.g. sesame-0.4.3153-2.el4),
   possibly on two different hosts.

   # service qpidd restart

   Do NOT run qpid-tool yet!

2. On MRG 1.3 host run qpid-tool.

   $ qpid-tool
   qpid: schema
   ... (you should see sysimage in this listing) ...
   qpid: list sysimage
   Object Summary:
   qpid: 


Actual results: No agent objects are listed.

Expected results: The sesame's sysimage object should appear with
  its ID.

Additional info: It is hard to reproduce this error with Condor QMFv1
  plugins as they are many and the agent objects start to show as soon
  as there is some other QMFv1 communication going on with the broker
  (e.g. just running 1.2 version of "qpid-tool <broker-IP>" makes the
  sesame object appear).

  The bug is apparent also in scenario of three hosts. One MRG 1.2
  which runs sesame against broker and two MRG 1.3 one of which is
  running qpidd, the other runs qpid-tool against the broker host.

  1.2 qpidd shows merely QMFv1 agents and lists sysagent QMFv1 objects
  almost immediately.