How to automate keystrokes for Blackberry J2ME Application?

Question

I am trying to do automation testing over a blackberry application written using J2ME over MIDlet architecture.

I have an application already running on blackberry devices. I am writing my TestApp (written again in J2ME) over existing App. (i.e., my TestApp extends to already Original App and it runs - inheriting).

I am trying to run the OriginalApp through my TestApp and handle the controls automatically using my TestApp. I am not able to automate the key strokes although I have already got the key codes of the blackberry device.

Keycodes I am using are like

KEY_BB_FIRE = -1204; 
KEY_BB_UP = -1200; 
KEY_BB_DOWN = -1201; 
KEY_BB_LEFT = -1202; 
KEY_BB_RIGHT = -1203;  

I am trying to use _keyPressed and _keyReleased methods of Screen class.

boolean sendKeys(Form obj, int keyObj){
    try{

        obj._keyPressed(keyObj);
        obj._keyReleased(keyObj);
                }
    catch (Exception e){
        System.out.println("ERROR: Striking key in Form failed: "+keyObj);
        return false;
    }

    return true;
}

Similarly I have got the key codes for Nokia device and I have completed automating the same application for Nokia. Just having trouble using the same technique on a blackberry.