How do I retrieve the data from AsyncTasks doInBackground()?

I'll keep this one as simple as I can.

I have a method in my control layer that uses a class CallServiceTask that extends AsyncTask. When calling new CallServiceTask().execute(parameters)
How do I retrieve the data returned from doInBackground? All the tutorials I've found use the class that extends AsyncTask directly from their Activity.
My problem is a little bit more complex than that.
All I want is to take the Object[] returned by doInBackground and set it to the private data members of my RestClient class.

CallServiceTask looks like this :

    private class CallServiceTask extends AsyncTask<Object, Void, Object[]>
{

    protected Object[] doInBackground(Object... params) 
    {
        HttpUriRequest req = (HttpUriRequest) params[0];
        String url = (String) params[1];

        return executeRequest(req, url);
    }
}

And my RestClient class looks like this:

public class RestClient
{

private ArrayList <NameValuePair> params;
private ArrayList <NameValuePair> headers;

private JSONObject jsonData;

private Object[] rtnData;

private String url;

private boolean connError;

public int getResponseCode() {
    return responseCode;
}

/**
 * 
 * @return  the result of whether the login was successful by looking at the response parameter of the JSON object. 
 */
public Boolean DidLoginSucceed()
{
    // Will Crash on socket error
        return ((JSONObject) rtnData[0]).optBoolean("response");
}

public String GetToken()
{
    return jsonData.optString("token");
}

public RestClient(String url)
{
    this.url = url;
    params = new ArrayList<NameValuePair>();
    headers = new ArrayList<NameValuePair>();
    rtnData = new Object[]{ new JSONObject() , Boolean.TRUE  };
}

public void AddParam(String name, String value)
{