The Java code seems to be correct. Now it would be helpful if you post code of your version of CustomFileResourceProvider.
Of course if you use the original CustomFileResourceProvider sample, it cannot load SSL resources. You need to add SSL connection/loading code there.
First I would recommend to add
[language=java:x3knzdo9]System.out.println( “resource request: ” + resource );[/language:x3knzdo9]
to the class and inspect the server’s log to make sure the loader is called.