stm32 Composite USB Host CDC

Using Keil uvision 5, I was finally able to get my device ( stm32f429) to emulate two Virtual Com Port in Windows successfully ( USB composite device), I can open two hyper terminal session with one VCP port each, and I can exchange data between them without problem. I use RTE to enable 1 USB device and 2 CDC Device class.

Now I want to do the same thing but in Host CDC mode, so I connected my device ( stm32f429 ) to an stm32F7 discovery board via FS usb connector. My problem is that in the new created project, I can't or I don't know how to enable 2 HOST CDC class using RTE manager.

If I use only one CDC device on the stm32f4 side, I'm able to communicate with it without problem, but when using 2 CDC device( on the F4 side) here I don't know how to do the stm32F7 side !

any advice would be greatly appreciated. thank you.

here some source code:

main.c:

/*------------------------------------------------------------------------------
 *        USB Host Thread
 *----------------------------------------------------------------------------*/
void USBH_Thread (void const *arg) {
  static bool con = false;
  int stat=0;

        stat = USBH_Initialize (0);                      /* Initialize USB Host 0        */

        stat = USBH_CDC_ACM_GetDeviceStatus(0);

        while( stat!=usbOK)     // Get error 0x21 "usbDeviceError", device dos not exist!
        { stat=USBH_CDC_ACM_GetDeviceStatus(0);
          osDelay (100);
                LED_On(0);
                osDelay (100);
                LED_Off(0);
        }

USBH_Config_CDC.h

//-------- <<< Use Configuration Wizard in Context Menu >>> --------------------

// <h>USB Host: Communication Device Class (CDC)
//   <o> Number of concurrent CDC Devices in system <0-3>
#define USBH_CDC_NUM                        2

//   <h>OS Resources Settings
//   These settings are used to optimize usage of OS resources.
//     <o>CDC Interrupt In Pipe (modem and error status reception) handling Thread Stack Size <64-65536>
#define USBH_CDC_INT_IN_THREAD_STACK_SIZE   512

//        CDC Interrupt In Pipe handling Thread Priority
#define USBH_CDC_INT_IN_THREAD_PRIORITY     osPriorityAboveNormal