wiFly RN-XV with breakout board to arduino

Hello,

For a project for school I need to create a wifi hotspot using my arduino (or some other microcontroller, but I am more familiar with arduinos from previous projects). They still had a wiFly RN-XV mounted on a WRL-11373 (which is a breakout board for xBees). This breakout board has 4 output connections, of which two are 5V and ground respectively. The other two are Dout and Din, and I cannot think of another thing then that they are the RX and TX ports of the wiFly shield. I tried to run the example file that is supplied with the "wiFly.h" library called "SpiUartTerminal", but I never got passed the message "Attempting to connect to SPI UART..." in the serial monitor. The code of this example is shown below:

/*

  SpiUartTerminal - tool to help troubleshoot problems with WiFly shield

  This code will initialise and test the SC16IS750 UART-SPI bridge then enable you
  to send commands to the WiFly module.

  Copyright (c) 2010 SparkFun Electronics. http://sparkfun.com LGPL 3.0

 */

#include "WiFly.h" // We use this for the preinstantiated SpiSerial object.


void setup() {

  Serial.begin(9600);
  Serial.println("SPI UART on WiFly Shield terminal tool");
  Serial.println("--------------------------------------");  
  Serial.println();
  Serial.println("This is a tool to help you troubleshoot problems with the WiFly shield.");
  Serial.println("For consistent results unplug & replug power to your Arduino and WiFly shield.");
  Serial.println("(Ensure the serial monitor is not open when you remove power.)");  
  Serial.println();
  
  Serial.println("Attempting to connect to SPI UART...");
  SpiSerial.begin();
  Serial.println("Connected to SPI UART.");
  Serial.println();
  
  Serial.println(" * Use $$ (with no line ending) to enter WiFly command mode. (\"CMD\")");
  Serial.println(" * Then send each command followed by a carriage return.");
  Serial.println();
  
  Serial.println("Waiting for input.");
  Serial.println();    
  
}


void loop() {
  // Terminal routine

  // Always display a response uninterrupted by typing
  // but note that this makes the terminal unresponsive
  // while a response is being received.
  while(SpiSerial.available() > 0) {
#if ARDUINO >= 100
    Serial.write(SpiSerial.read());
#else
    Serial.print(SpiSerial.read(), BYTE);
#endif
  }
  
  if(Serial.available()) { // Outgoing data
#if ARDUINO >= 100  
    SpiSerial.write(Serial.read());
#else
    SpiSerial.print(Serial.read(), BYTE);
#endif
  }
}

Because there is no pin specified that has to be connected to the Din and Dout within the given code, I imagined these could be the RX and TX UART pins on the arduino uno (pin 0 and 1), or the SPI Master-out-Slave-in and Master-in-Slave-out pins (pin 11 and 12). I also tried some other random pins, just to be sure, but none worked. The problem apparently therefore is in the "SpiSerial.begin()" line. I tried to google this problem, but searching for the breakout board, and therefore its output pins, turned out to be rather difficult, since there are a lot of suppliers of this breakout board that came up first in google. Also looking for the "Attempting to connect to SPI UART..." line on google or looking into the schematics of the RN-XV wiFly shield were not enough to solve the problem.

Can someone help me to find out what I am doing wrong? There are 4 LEDs on the breakout board, the LED indicating power is on, the other three LEDs (DIN, DOUT, and RSSI) are all off. I do use headers, and they are soldered on top as well.