Weird UrlMappings behavior for Grails 1.2.1

Question

I've created a Grails (1.2.1) application in SpringSource Tools Suite 2.3.2 and here is my UrlMappings.groovy:

class UrlMappings {
    static mappings = {
      "/$controller/$action?/$id?"{
       constraints {
    // apply constraints here
    }
   }

      "/broadcasters/setInterval" { //cause a 404
            controller = "broadcaster"
            action = "setRefreshInterval"
      }

      "/broadcasters/online/$id?" { //this one is OK
       controller = "broadcaster"
       action = "listOnlineBroadcasters"
      }
      "/broadcasters/$id?" { //this one is OK
       controller = "broadcaster"
       action = "listAllBroadcasters"
      }
      "/" (controller: "login", action:"auth")
      "/logout" (controller: "logout")
   "500"(view:'/error')
   "404"(view:'/404')
 }
}

Here is my controller

package xxx.yyy.controllers

import org.codehaus.groovy.grails.plugins.springsecurity.Secured

@Secured(['ROLE_ADMIN'])
class BroadcasterController {

 def broadcasterService
 static defaultAction = "listAllBroadcasters"

    def listOnlineBroadcasters = {
        ...
    }

    def listAllBroadcasters = {
        ...
    }

 def setRefreshInterval = {
  ...
 }
}

When I access the url /broadcasters/setInterval, I've got a 404 both as normal or ajax request. I also write a simple unit test to check the for my UrlMappings:

class GSMUrlMappingTests extends GrailsUrlMappingsTestCase {
    void testUrlMapping() {
        assertUrlMapping ("/broadcasters/setInterval", controller: "broadcaster", action: "setRefreshInterval")
    }
}

And the test failed! Is it a bug of Grails 1.2.1 or am I missing something? Here is the plugins I've used

plugins.acegi=0.5.2
plugins.debug=1.0.2
plugins.hibernate=1.2.1
plugins.jdbc-pool=0.1
plugins.tomcat=1.2.1

Thanks in advanced for your replies!