Ok, I think you need some other way of monitoring the serial data just to eliminate some possible sources of error.
Do you have a USB-TTL serial adapter that you can connect to your PC?
If so, you can connect GND of the USB-TTL serial adapter to the GND of your Arduino. Connect the softwareserial TX pin on your Arduino to the RXI pin of the USB-TTL serial adapter. Setup a PC COM port to the same baud rate you have in your code. You will need a teminal emulator program that can display hexadecimal bytes (such as RealTerm).
You should see the bytes that you are transmitting displayed on your PC. If they are the same as the bytes in your request[] array, then you are at least transmitting the correct data.
Next connect the softwareserial RX pin on your Arduino to the RXI pin of the USB-TTL serial adapter.
You should see the response from the other device on your PC.