Eclipse ignoring Class-Path value in custom MANIFEST.MF

I try to export a project with binaries and sources as a JAR file which depends on third-party JAR files.

I copied the required files to the project home location and wrote a MANIFEST.MF file which I then chose via the "Export JAR" wizard. However, the class-path instruction is completely ignored by the Eclipse wizard keeping everything but the class-path line开发者_如何学JAVA.

This is my MANIFEST.MF:

Manifest-Version: 1.0
Main-Class: com.org.StartEnv
Class-Path: util.jar

When I manually change the Manifest.mf in the resulting JAR file, everything works as expected.

Eclipse Java EE IDE for Web Developers, Indigo, Build id: 20110615-0604.