AngularJS: passing complex json data using $http.post

I'm having trouble passing a complex json object in angularjs with $http.post. I'm keep getting a 400 bad request error sent back from the server saying the request was syntactically incorrect. I believe it has something to do with the array since it passes fine when i don't include it.

json i'm passing.

{
    customer: {
        firstName: "John",
        lastName: "Doe",
        street: "1234 South Dr",
        city: "Detroit",
        state: "MI",
        zip: "12345",
        phone: "123-321-1234",
        email: "[email protected]"
    },
    order: {
        orderDate: "06-16-2015",
        registerNum: "1",
        transactionNum: "7820",
        deliveryStatusID: 1,
        notes: "Hold order until July",
        items: [
            {skuID: "1234568",
             skuDescription: "Order item 1",
             qty: "4",
             itemStatusID: 1,
             itemStatusDescription: "Backorder"
             },
            {skuID: "7387491",
             skuDescription: "Order item 2",
             qty: "1",
             itemStatusID: 1,
             itemStatusDescription: "Flagged"
            }
        ]
    }
}

angular service function

this.addOrder = function(new_order) {
    return $http.post(base + "/add", new_order);
};

Spring MVC controller method

@RequestMapping(value="/add", method=RequestMethod.POST)
public void addOrder(@RequestBody CustomerOrder customerOrder) {

    System.out.println("----CUSTOMER-INFO----");
    System.out.println(customerOrder.getCustomer().getFirstName());
    System.out.println(customerOrder.getCustomer().getLastName());

    System.out.println("");
    System.out.println("----ORDER-INFO----");
    System.out.println(customerOrder.getOrder().getOrderID());
    System.out.println(customerOrder.getOrder().getOrderDate());       

}

The problem only seems to occur when I pass the items array in the json. I've passed the same json object without the items array and it works fine. The format of the json is being sent in the same format that gets returned whenever I GET an order with my angularjs service method so I'm really not sure as to where I'm going wrong with this.

If I need to provide more code please let me know. I appreciate any effort in helping me out.

Thank you.

Jason