As reported earlier, it's not clear when the new orocos_toolchain_ros packages
for Lucid will be released. In case you want to test the newly built packages
nevertheless, you can:

# Change 'ros/ubuntu' to 'ros-shadow-fixed/ubuntu':
sudo edit /etc/apt/sources.list.d/ros-latest.list
sudo apt-get update
sudo apt-get upgrade
# Change 'ros-shadow-fixed/ubuntu' back to 'ros/ubuntu':
sudo edit /etc/apt/sources.list.d/ros-latest.list
sudo apt-get update

This is at your own risk of course, if the apt-get upgrade step fails, you'll
have to re-do the upgrade after you changed back to ros/ubuntu to get your old
state back.

Peter