I find some problematic behaviour with RenderKit decoration that didn't match the spec. I submitted a bug to Sun and it looks as if it's been fixed.

https://javaserverfaces.dev.java.net/issues/show_bug.cgi?id=1112

So we should be able to continue our investigation here.

RenderKit decoration is confirmed to be working. The proposed feature is as follows:

By default, the addition of icefaces.jar enables ICEfaces for all JSF pages in the application.
A parameter: org.icefaces.render.auto = true (default behavior) = false (individual pages are configured for ICEfaces rendering).
A tag/component: <ice:config render="true" /> configures ICEfaces rendering on specified pages.

The configuration component is useful for general ICEfaces per-page configuration (fictitious attributes to start the discussion):

<ice:config render="true" pushheartbeat="50s" profile="mobile" submitstrategy="delta" />

The following cryptic Exception can be observed when the RenderKit is null, indicating that the page still contains <f:view renderKitId="xHTML_BASIC" contentType="text/html" >

java.lang.NullPointerException
at com.sun.faces.application.ApplicationImpl.applyAnnotations(ApplicationImpl.java:1870)
at com.sun.faces.application.ApplicationImpl.createComponentApplyAnnotations(ApplicationImpl.java:1819)
at com.sun.faces.application.ApplicationImpl.createComponent(ApplicationImpl.java:1090)
at com.sun.faces.facelets.tag.jsf.ComponentTagHandlerDelegateImpl.createComponent(ComponentTagHandlerDelegateImpl.java:326)
at com.sun.faces.facelets.tag.jsf.ComponentTagHandlerDelegateImpl.apply(ComponentTagHandlerDelegateImpl.java:145)
at javax.faces.view.facelets.DelegatingMetaTagHandler.apply(DelegatingMetaTagHandler.java:114)
at javax.faces.view.facelets.CompositeFaceletHandler.apply(CompositeFaceletHandler.java:91)
at com.sun.faces.facelets.compiler.NamespaceHandler.apply(NamespaceHandler.java:86)
at javax.faces.view.facelets.CompositeFaceletHandler.apply(CompositeFaceletHandler.java:91)
at com.sun.faces.facelets.compiler.EncodingHandler.apply(EncodingHandler.java:75)
at com.sun.faces.facelets.impl.DefaultFacelet.apply(DefaultFacelet.java:145)
at com.sun.faces.application.view.FaceletViewHandlingStrategy.buildView(FaceletViewHandlingStrategy.java:715)
at com.sun.faces.lifecycle.RenderResponsePhase.execute(RenderResponsePhase.java:106)
at com.sun.faces.lifecycle.Phase.doPhase(Phase.java:101)
at com.sun.faces.lifecycle.LifecycleImpl.render(LifecycleImpl.java:139)
at javax.faces.webapp.FacesServlet.service(FacesServlet.java:311)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:290)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:206)
at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:233)
at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:191)
at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:128)
at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:102)
at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:109)
at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:286)
at org.apache.coyote.http11.Http11Processor.process(Http11Processor.java:845)
at org.apache.coyote.http11.Http11Protocol$Http11ConnectionHandler.process(Http11Protocol.java:583)
at org.apache.tomcat.util.net.JIoEndpoint$Worker.run(JIoEndpoint.java:447)
at java.lang.Thread.run(Thread.java:637)