Eclipse Plug-in Development

I've hit this issue before, but it took much effort to rediscover the answer, so I'm writing it down this time...

When you create a plug-in that simply packages and re-exports pre-existing JAR files, make sure that the following things are true:

1. the JARs are all listed in the project build path ("Libraries" tab)
2. the JARs have all been exported in the project build path ("Order and Export" tab)
3. the JARs are all listed in the 'Classpath' list in the manifest ("Runtime" tab)
4. the JAR packages that you wish to export (normally all of them) are listed in the export listof the manifest ("Runtime" tab)
5. the JARs are all selected in the binary build list of the manifest ("Build" tab)

I had done all of these steps but #2.  A dependent plug-in complained that package names could not be resolved -- even though all other signs indicated that the packages were accessible.