I've found the reason this failed. After dissecting the help plugin I've found additional extensions defined that allowed Equinox to use help files supplied in the plugin project as accessible resources. This is what I put in plugin.xml in extensions' section:
<extension point="org.eclipse.help.webapp.view">
<view class="plugin.CustomView"></view>
</extension>
<extension point="org.eclipse.equinox.http.registry.httpcontexts">
<httpcontext id="help">
<resource-mapping path="/"> </resource-mapping>
</httpcontext>
</extension>
<extension point="org.eclipse.equinox.http.registry.resources">
<resource alias="/help" base-name="/help" httpcontextId="help"> </resource>
</extension>
The firs one is the actual view definition class. Next is the help context pointing on the plugin's root and the last is actual folder containing JSP files, it's position relative to the plugin's root and alias as available for the browser. After adding those Information Center in my application displays my test HTML code in the new tab. The same goes for other extension points in help plugin that add new JSP-based views in Information Center.
[Updated on: Thu, 08 August 2013 06:50] by Moderator