Can't find schema for an extension point

I want to add an extension to my project, extensionpoint "org.eclipse.wst.xsl.ui.contentAssistProcessor", but I'm unable to load the schema. I keep getting an error message:

JAR entry /schema/contentAssistProcessor.exsd not found in C:\Program Files (x86)\eclipse-rcp-helios-SR1-win32\eclipse\plugins\org.eclipse.wst.xsl.ui.source_1.1.1.v201009091745.jar


java.io.FileNotFoundException: JAR entry /schema/contentAssistProcessor.exsd not found in C:\Program Files (x86)\eclipse-rcp-helios-SR1-win32\eclipse\plugins\org.eclipse.wst.xsl.ui.source_1.1.1.v201009091745.jar
    at sun.net.www.protocol.jar.JarURLConnection.connect(JarURLConnection.java:122)
    at sun.net.www.protocol.jar.JarURLConnection.getInputStream(JarURLConnection.java:132)
    at java.net.URL.openStream(URL.java:1010)
    at org.eclipse.pde.internal.core.util.SchemaUtil.getInputStream(SchemaUtil.java:40)
    at org.eclipse.pde.internal.core.util.SchemaUtil.parseURL(SchemaUtil.java:46)
    at org.eclipse.pde.internal.ui.wizards.extension.PointSelectionPage.handlePointSelection(PointSelectionPage.java:524)
    at org.eclipse.pde.internal.ui.wizards.extension.PointSelectionPage.selectionChanged(PointSelectionPage.java:489)
    at org.eclipse.jface.viewers.Viewer$2.run(Viewer.java:162)
    at org.eclipse.core.runtime.SafeRunner.run(SafeRunner.java:42)
(snip)

If I want to see the extension point description I get a page showing:

Identifier: null.null

Description: 

Configuration Markup:

The plugin has been added to my dependencies (done automatically by eclipse) and is added to my project build path.

The plugin has been installed from the update site http://download.eclipse.org/webtools/repositor开发者_运维问答y/helios/, latest version 3.2.2

When I look at my plugins directory, I can see both "org.eclipse.wst.xsl.ui.source_1.1.1.v201009091745.jar" and "org.eclipse.wst.xsl.ui_1.1.1.v201009091745.jar"

Unzipping them shows nothing wrong, the schema is there and looks ok.

The error message I'm getting is the same as in the this Eclipse bug which the submitter says is due to:

Actually, the underlying issue is that the org.eclipse.equinox.registry plug-in does not export the schema folder to the source bundle. I'll file a bug for them.

I've tried to uninstall the webtools plugins and reinstalling them with no result.

Edit: I have manually started and diagnosed the wst.xsl.ui plugin throught the plugin registry without and problems, so there doesnt seem to be a dependency issue.

I'm running out of things to try...

I'd recommend importing the wst.ui bundle into your workspace as a source project. You can do this through: File -> Import... -> Plugins and Fragments. Select the org.eclipse.wst.xsl.ui and choose project with source folders. The schema directory should be imported along with it, but if it's not, you may need to manually import it (ie- copy and paste from the zip file).

This will ensure that the exsd is available.