Help Sending Commands to a USB Device(Prolific) with modified Deva Example

Hi, all
Recently I bought my first iMac and start to learn programming on Mac
my first project is a small USB communication program.
I have a USB device which has a red light on it,
and I also have the command list of this device.

The capabilities of the device allow me to turn on/off the light.

this is an examples of the commands listed in the document:
- Turn light on
Initial code: 0x00
Command: 0xFF
Data: 0xCC
Check Sum: 0xDD
Ending Code: 0xEE

- Turn light off
Initial code: 0x00
Command: 0xFF
Data: 0xAA
Check Sum: 0xBB
Ending Code: 0xEE

I changed the VID & PID in the "Deva Example" and it works in the first initial sequence but when the program jump into
"SetIoPortsConfig()" there comes an error:

---Debugger console output start---
Running...
Found device VID 0x067B (1659), PID 0x2303 (8963), release 768
Configuration value is 1
3 endpoints found
Endpoint 1: Interrupt In 1, max packet 10, interval 1
Endpoint 2: Bulk Out 2, max packet 64, interval 0
Endpoint 3: Bulk In 3, max packet 64, interval 0
Now we actually get to do something with this device, wow!!!!
Doing ReadIoPorts with portbits ffffffff
unable to do ReadIoPorts (0xE000404F) USB error 79(0x4F)
Debugger stopped.
Program exited with status value:0.
---Debugger console output end---

I have traced the code of "Deva Example" to :
void finallyDoSomethingWithThisDevice(IOUSBInterfaceInterface245 **intf)
{
.....
#else
IOReturn err;
UInt32 portBits, IOBits, IOBits1;
UInt32 light, light2;
Boolean dirn;
// First set all ports to input
err = DevaSetIoPortsConfig(intf, 0x000FFFFF); // and then I step into this function
}

// encounter an error in this function
IOReturn DevaSetIoPortsConfig(IOUSBInterfaceInterface245 **intf, UInt32 portBits)
{
IOUSBDevRequest req;
IOReturn err;

req.bmRequestType = USBmakebmRequestType(kUSBOut, kUSBVendor, kUSBDevice);
req.bRequest = 0xF0; // SetIoPortsConfig
req.wValue = 0; // unused
req.wIndex = 0; // unused
req.wLength = 4; // 32bit int
req.pData = &portBits;

portBits = HostToUSBLong(portBits);
// 000CBBAA <-port mappings
// 1 is Input (looks like I, 0 is output, looks like O)
#if NARRATEIO
printf("Doing SetIoPortsConfig with portbits %08x\n", USBToHostLong(portBits));
#endif

err = (*intf)->ControlRequest(intf, 0, &req);
if (kIOReturnSuccess == err)
{
if(req.wLenDone != 4)
{
err = kIOReturnUnderrun;
}
}
return(err);
}

---my question---
How do I replace and insert the command provided in the document, I am really sorry I have tried Google, official website of Prolific Technologies
but I have no clue about the right format, any replies will be highly appreciated. Thank you so much!

--my USB device specification--

USB-Serial Controller:
Product ID: 0x2303
Vendor ID: 0x067b (Prolific Technology, Inc.)
Version: 3.00
Speed: Up to 12 Mb/sec
Manufacturer: Prolific Technology Inc.
Location ID: 0x06400000
Current Available (mA): 500
Current Required (mA): 100

deviceName: USB-Serial Controller
Location ID: 0x6400000
Device Class: 0x0
Device Speed: 0x1
Device Vendor ID: 0x67b
Device Product ID: 0x2303
Device Address: 0x3
Device Configuration: 0x1

--Detail Device and Interface Inforamtion in IORegistryExplore--
Device

Interface 1

Interface 2

--Apple Developer Reference Example--
Deva Example
USB Private Data Sample