I believe you need to install the plugin:
"Logging with SLF4J and Logback"
This should be available by choosing Help->Install New Software.
Selecting the Eclipse Download URL for your Eclipse version. e.g. for Juno the URL is:
Juno - http://download.eclipse.org/releases/juno/201209280900
then choosing "Logging with SLF4J and Logback" to install.
Hope that helps.