Ok I am running with Eclipse Kepler. Tried today to set it up for Tomcat 8, but the adapter won't appear in the list.
Googled a bit and found tutos on SO, nixmash and vitalflux, which all sum up the same way: download the last 3.6 Eclipse WTP and unzip it in your eclipse directories.
But I don't want a whole upgrade of my Kepler to the Luna WTP version (In my understanding, this is what would actually happen). I am looking for a way to pick only the server adapters. How do I do that?