The Update Manager tends to do it's own thing and keep you up with the latest packages. I haven't figured out how to make Update Manager keep packages where they are and so I use apt-get to "pin" packages to a specific version. NB - all of the package management systems tend to do this differently so you'll have to chose one package manager and stick with it.
First, install the package version that you want.
Next, use apt-cache policy to see which version you are using:
$$ apt-cache policy xterm
xterm:
Installed: 241-1ubuntu1
Candidate: 241-1ubuntu1
Version table:
*** 241-1ubuntu1 0
500 http://us.archive.ubuntu.com jaunty/main Packages
100 /var/lib/dpkg/status
Finally, edit /etc/apt/policies and add an entry for your package:
Package: xterm
Pin: version 241*
Priority: 1001
Now you can run:
$sudo apt-get update
$sudo apt-get upgrade
and your package will be kept at the current version. If you want to over-ride this use dist-upgrade:
$sudo apt-get dist-upgrade