Why doesn't my listener for the background analog output change what values it queues?

I want to dynamically update the values in the analog output data queue. I've included my attempt below. Initially, the variable called 'signal' is a vector of values going from 0 to 5 (and back to 0). However, I change the contents of 'signal' with all 1's. Nonetheless, with a scope connected to the AO, it simply rises from 0 to 5 again and again. This doesn't go to 1 after the initial queue runs out.

%Initialize DA Device 'Dev1' - PCI-6713 - AO
  daqreset %reset daq
  sAO = daq.createSession('ni'); %create a DAQ session for NI card
  sAO.Rate = 100; %Update AO 100 times per second
  ch = addAnalogOutputChannel(sAO,'Dev1', 'ao1', 'Voltage'); %Add daq device and channel to session
  signal = [linspace(0,5,299)';0]; %Incremental values from 0 to 5V ending back at 0.
  queueOutputData(sAO,signal) %buffer some output

    %Start AI/AO tasks
    sAO.IsContinuous = true; %NECESSARY AND NOT IN DOCUMENTATION
    lhAO = addlistener(sAO,'DataRequired', @(src,event)newNumbers(src,event,signal));
    startBackground(sAO);

    %Change values to buffer in the output queue
    signal = ones(300,1);
    pause(); %await keypress
    delete(lhAO)
    stop(sAO)
    disp('Done')

    function newNumbers(src, event, varargin)
        signal = varargin{1};
        queueOutputData(src,signal);
    end

Since resources are limited on the topic I'm happy to point you to my resources for developing this code:

1. Additional Arguments for Callback Function
2. Generate continuous background analog output

Answer 1

[Ben Don]

I eventually got this working using the functions evalin('ws','var') and assignin('ws','var',value). Hopefully these two functions are useful to whomever goes looking for anything related to the topic above.

1. evalin()
2. assignin()