[Error 401] problem getting container managed security working with Grails/Jetty

I am having trouble getting standard JEE security working with Grails and Jetty.  How do I get this working with Grail's Jetty?

Here's what I tried.

I altered RunApp.groovy and added (for configureHttpServer)

HashUserRealm myrealm = new HashUserRealm("MyRealm","${grailsHome}/conf/realm.properties");
server.setUserRealms((UserRealm[])[myrealm]);

that's based on what I saw here:
http://docs.codehaus.org/display/JETTY/How+to+Configure+Security+with+Embedded+Jetty

then I added that same security xml into web2.4template.xml.
and of course I created the realm.properties files for the HashUserRealm

It's starts up without error, but loading the app in the browser, I get:
Error 401 - Internal Error.

And the shell output was just:
INFO:  Initializing Spring FrameworkServlet 'grails-errorhandler'

I also tried the programmatic security without a web.xml with the same result.

any help is appreciated.