Description of problem:
I had a client registered to a Satellite and assigned to a RHEL channel (rhel-i386-server-5).

# yum list all
didn't list any packages from the default RHEL channel even after
#yum clean all
on the client or "Update" button on the Satellite WEBUI channel page.

According to WEBUI there were 5142 in the RHEL channel.

Version-Release number of selected component (if applicable):
Satellite-5.3.0-RHEL5-re20090401.0-x86_64

Steps to Reproduce:
1. Synchronize a RHEL channel on a satellite.
My first sync failed for some reason and the WEBUI showed 0 packages in the channel. (Not sure how to reproduce it - maybe interrupt the sync process - but the step seems to be important.)
The result PROBABLY was that a repodata cache with 0 packages in the channel was created. 
2. I run the satellite-sync again. The sync was successful and according to WEBUI 5142 packages were in the RHEL channel.
3.
Run
# yum repolist
on the client to make sure, it is subscribed to the channel.
4.
Run
# yum list all
on the client
  
Actual results:

Commands on client:
# yum list available (or all)
doesn't list any package from the RHEL channel.
# yum install <package>
fails, if the <package> is included in the RHEL channel according to WEBUI.
# yum search <package>
doesn't find the package that is definitely included in the channel.

Expected results:
I expect aligned information - on WEBUI and for the clients. If WEBUI shows over 5000 packages in the channel, the client shall have there packages available.

Additional info:
It seems that the channel meta data will be created once and won't be updated any again.
When I removed /var/cache/rhn/repodata/ on the satellite and run satellite-sync again, the cache will be re-created correctly.

The reason of the problem can be similar to BZ#493817.