AMF body dropped on Deserialization

I am trying to do a simple Flex AMF call to a ColdFusion server via BlazeDS. Using a RemoteObject, I am trying to send a login request to the server, and responding with success or failure. For some reason, when the data gets to BlazeDS, the body of the message gets dropped during deserializaion(I think). Here is my ColdFusion/BlazeDS log code and the CFC and Flex ActionScript call.

Any and all help is appreciated. Thank!

[BlazeDS]Channel endpoint my-cfamf received request.
[BlazeDS]Deserializing AMF/HTTP request
Version: 3
  (Message #0 targetURI=null, responseURI=/3)
    (Array #0)
      [0] = (Typed Object #0 'flex.messaging.messages.RemotingMessage')
        source = "service.UserService"
        operation = "authenticateUser"
        destination = "ColdFusion"
        timesta开发者_StackOverflowmp = 0
        headers = (Object #1)
          DSEndpoint = "my-cfamf"
          DSId = "883A97CF-4A08-0B8E-9056-1BF562A40EB4"
        body = (Array #2)
          [0] = "Username"
          [1] = "Password"
        clientId = null
        messageId = "D1743AB9-54B8-E73C-85C7-E990DE7F1ECE"
        timeToLive = 0

[BlazeDS]Before invoke service: remoting-service
  incomingMessage: Flex Message (flex.messaging.messages.RemotingMessage) 
    operation = authenticateUser
    clientId = 883AAF5D-900B-410A-1E8B-3B3FBD6552A6
    destination = ColdFusion
    messageId = D1743AB9-54B8-E73C-85C7-E990DE7F1ECE
    timestamp = 1300998708880
    timeToLive = 0
    body = null
    hdr(DSId) = 883A97CF-4A08-0B8E-9056-1BF562A40EB4
    hdr(DSEndpoint) = my-cfamf


-- Flex
            remoteUserService = new RemoteObject;
            remoteUserService.destination = "ColdFusion";
            remoteUserService.source = "service.UserService";
            remoteUserService.authenticateUser.addEventListener("result",  authenticate_requestComplete);
            remoteUserService.authenticateUser.addEventListener("fault",  authenticate_requestFailure);     
            remoteUserService.authenticateUser({username:username, password:password});

-- ColdFusion

    <cffunction name="authenticateUser" access="remote" returnType="Struct">
        <cfargument name="username" type="string">
        <cfargument name="password" type="string">


        <cfset ret = getAuthenticationService().authenticate(username, password) />

        <cfreturn ret>
    </cffunction>

Why not pass the credentials across as two strings instead of creating an object? That way they will show up in your arguments scope in CF. Alternatively you can package then in a data transfer object but that seems like overkill for this.