Date format and possible null values

I love datatables, it has made my project so much easier to develop.

I am getting my data from an Ajax call and one of those columns is a date which can have a null value. I want to format the date value to be the same as a toDateString call on a Javascript Date. How can I achieve this? I have tried the below.

 $('#scheduledata').dataTable({
    "bProcessing": true,
    "bDestroy": true,
    "sAjaxDataProp": "triggerList"
    "sAjaxSource": "/freewheel/api/triggers/queued"
    "aoColumns": [
      {"mData": "trigger.job.@uid"}
      {"mData": "trigger.job.@name"}
      {"mData": "trigger.runDate", "sDefaultContent": (new Date()).toDateString(), "dateFormat": "dd/MM/yyyy" }
      {"mData": "trigger.triggerTime"}
      {"mData": "trigger.job.executingServer.@name"}
    ]
    "aaSorting": [
      [2, "asc"]
      [3, "asc"]
    ],
    "aoColumnDefs": [
      { "bSearchable": false, "bVisible": false, "aTargets": [0]}
    ],
    "bJQueryUI": true
  })

The JSON response is this.

{
  "triggerList": [
    {
      "trigger": {
        "@type": "RepeatingTrigger", 
        "@uid": "32768", 
        "job": {
          "@name": "Test Job", 
          "@stderr": "stderr.log", 
          "@stdout": "stdout.log", 
          "@type": "CommandJob", 
          "@uid": "65536", 
          "command": "java -version", 
          "executingServer": {
            "@name": "localhost", 
            "@port": "12145", 
            "@uid": "1"
          }, 
          "jobType": "COMMAND"
        }, 
        "triggerInterval": "50000", 
        "triggerTime": "23:01:07.174", 
        "triggerType": "REPEATING"
      }
    }, 
    {
      "trigger": {
        "@type": "TimedTrigger", 
        "@uid": "32769", 
        "daysOfWeek": [
          "MONDAY", 
          "TUESDAY", 
          "WEDNESDAY", 
          "THURSDAY", 
          "FRIDAY"
        ], 
        "job": {
          "@name": "Test Job2", 
          "@stderr": "stderr.log", 
          "@stdout": "stdout.log", 
          "@type": "CommandJob", 
          "@uid": "65537", 
          "command": "java -version", 
          "executingServer": {
            "@name": "localhost", 
            "@port": "12145", 
            "@uid": "1"
          }, 
          "jobType": "COMMAND"
        }, 
        "runDate": "2013-06-03+01:00", 
        "triggerTime": " 1:07:37.772", 
        "triggerType": "TIMED"
      }
    }
  ]
}

As you can see the first entry has no runDate value so it correctly uses the current date in the format I want, but the second entry has a date and I get the data presented to the UI exactly as you see it here.

I also have another table that has a date/time column which I would like formatted as 'DDD dd MM yyyy hh:mm:ss'

Any pointers will be very much appreciated.

Thanks