Yum priorities plugin

On a PC with Fedora 13 x86_64 I have several active repositories with
different priorities.
 [fedora]
      priority=1
 [updates]
      priority=1
 ...
 [adobe-linux-i386]
      priority=20

When I do:
 # LANG=en_US.utf8 yum install libstdc++.so.6
 Loaded plugins: presto, priorities, refresh-packagekit
 ...
 Dependencies Resolved
 ===================================================================================================================
  Package                       Arch              Version Repository                     Size
 ===================================================================================================================
 Installing:
  AdobeReader_sve               i486              8.1.7-1 adobe-linux-i386               51 M
 ...

Yum wants to install AdobeReader_sve because it provides libstdc++.so.6
as reported here [1] too.

Shouldn't the priorities yum plugin avoid to install AdobeReader_sve,
and go with the classic libstdc++ package in the [fedora] or [updates]
repository?

Thank you in advance.

[1] http://lists.fedoraproject.org/pipermail/users/2010-May/373309.html

-- 
Stefano Biagiotti