If this is not showing up then maybe the file is corrupt / having issues being read in. Try deleting the project (and the files on disk) and downloading the zip again.
My Type Space view looks similar to what you have, but the "ExtJSTL-4.1.zip" is not there. It appears as though no matter what I try doing I cannot get the internal ZIP file in the ExtJSTL-4.1 project to load.
If you are still experiencing this issue I suggest you update to Sencha Eclipse Plugin. 1.1 version was released on 11/6/2012.
To upgrade go to the support portal (support.sencha.com) and downloaded the latest Sencha Complete installer, or the unbundled installer that's on the portal.