Synaptic doesn't honor pinning rules in /etc/apt/preferences.d/

I have a Lucid system installed, but I wanted to test the kernels from Maverick. To accomplish this, I added the Maverick repositories to my /etc/apt/sources.list file, but I setup apt pinning to only get kernel updates from Maverick. To setup the apt pinning I created a file:

/etc/apt/preferences.d/maverick-pin with the following contents:

   Package: linux-image-generic-pae
   Pin: release o=Ubuntu,a=maverick
   Pin-Priority: 500

   Package: *
   Pin: release o=Ubuntu,a=maverick
   Pin-Priority: 400

When I ran "apt-get dist-upgrade" it correctly showed that a new kernel version was available and I installed it. After the upgrade I ran "apt-get upgrade -uV" again to make sure I was completely up to date. Here was the output:

   $ sudo apt-get upgrade -uV
   Reading package lists... Done
   Building dependency tree
   Reading state information... Done
   0 upgraded, 0 newly installed, 0 to remove and 0 not upgraded.

I launch Synaptic to search for a new package to install, and it tells me that I have many updates available, but it seems to be ignoring the pinning rules I've setup.

One package it tells me I should upgrade is "acpid". When I run "apt-cache policy acpid" it shows me that there is a newer version in Maverick, but because of the pinning rules that newer version should not be considered for upgrade:

acpid:
  Installed: 1.0.10-5ubuntu2.1
  Candidate: 1.0.10-5ubuntu2.1
  Version table:
     1.0.10-5ubuntu4 0
        400 http://us.archive.ubuntu.com/ubuntu/ maverick/main Packages
 *** 1.0.10-5ubuntu2.1 0
        500 http://us.archive.ubuntu.com/ubuntu/ lucid-updates/main Packages
        100 /var/lib/dpkg/status
     1.0.10-5ubuntu2 0
        500 http://us.archive.ubuntu.com/ubuntu/ lucid/main Packages