JAX-WS Tools has the following minimum requirements.
Eclipse 3.4.0 (http://www.eclipse.org/downloads)
Eclipse Web Tools Platform (WTP) 3.0.1 (http://download.eclipse.org/webtools/downloads)
Java 5.0 is the minimum required version and JDK 6.0 is supported from update 4 and later.
http://java.sun.com/javase/downloads/
Before creating Web service applications with JAX-WS Tools a JAX-WS runtime must be downloaded, installed and configured in the workbench.
Currently we support the Apache CXF runtime for JAX-WS development from version 2.0.6 upwards. CXF 2.1.x or greater recommended.
The Apache CXF runtime can be downloaded from the Apache CXF Downloads page.
See here for a note on using CXF 2.6.0.
Apache CXF 2.x Preferences