LPC1756 HID mouse, no IN report interrupt

Hi, I'm trying to implement the generic USB mouse functionality on NXP LPC1756. Basing on Keil LED HID example, I modified the USB descriptor as following:

/* HID Report Descriptor */
const uint8_t HID_ReportDescriptor[] = {
  HID_UsagePage(0x01),
  HID_Usage(0x02),
  HID_Collection(HID_Application),
    HID_Usage(0x01),
        HID_Collection(HID_Physical),
        HID_UsagePage(HID_USAGE_PAGE_BUTTON),
    HID_UsageMin(1),
    HID_UsageMax(3),
    HID_LogicalMin(0),
    HID_LogicalMax(1),
        HID_ReportCount(3),
        HID_ReportSize(1),
    HID_Input(HID_Data | HID_Variable | HID_Absolute),
    HID_ReportCount(1),
        HID_ReportSize(5),
    HID_Input(HID_Constant),
    HID_UsagePage(HID_USAGE_PAGE_GENERIC),
    HID_Usage(HID_USAGE_GENERIC_X),
        HID_Usage(HID_USAGE_GENERIC_Y),
        //HID_Usage(HID_USAGE_GENERIC_WHEEL),
    HID_LogicalMin(-127),
    HID_LogicalMax(127),
    HID_ReportSize(8),
        HID_ReportCount(2),
    HID_Input(HID_Data | HID_Variable | HID_Relative),
  HID_EndCollection,
  HID_EndCollection
};

const uint16_t HID_ReportDescSize = sizeof(HID_ReportDescriptor);


/* USB Standard Device Descriptor */
const uint8_t USB_DeviceDescriptor[] = {
  USB_DEVICE_DESC_SIZE,              /* bLength */
  USB_DEVICE_DESCRIPTOR_TYPE,        /* bDescriptorType */
  WBVAL(0x0200), /* 2.00 */          /* bcdUSB */
  0x00,                              /* bDeviceClass */
  0x00,                              /* bDeviceSubClass */
  0x00,                              /* bDeviceProtocol */
  USB_MAX_PACKET0,                   /* bMaxPacketSize0 */
  WBVAL(0xc251),                     /* idVendor */
  WBVAL(0x0116),                     /* idProduct */
  WBVAL(0x0100), /* 1.00 */          /* bcdDevice */
  0x04,                              /* iManufacturer */
  0x20,                              /* iProduct */
  0x42,                              /* iSerialNumber */
  0x01                               /* bNumConfigurations */
};

/* USB Configuration Descriptor */
/*   All Descriptors (Configuration, Interface, Endpoint, Class, Vendor */
const uint8_t USB_ConfigDescriptor[] = {
/* Configuration 1 */
  USB_CONFIGUARTION_DESC_SIZE,       /* bDescriptorType */
  USB_CONFIGURATION_DESCRIPTOR_TYPE, /* bDescriptorType */
  WBVAL(                             /* wTotalLength */
    USB_CONFIGUARTION_DESC_SIZE +
    USB_INTERFACE_DESC_SIZE     +
    HID_DESC_SIZE               +
    USB_ENDPOINT_DESC_SIZE
  ),
  0x01,                              /* bNumInterfaces */
  0x01,                              /* bConfigurationValue */
  0x00,                              /* iConfiguration */
  USB_CONFIG_BUS_POWERED /*|*/       /* bmAttributes */
  USB_CONFIG_POWER_MA(100),          /* bMaxPower */
/* Interface 0, Alternate Setting 0, HID Class */
  USB_INTERFACE_DESC_SIZE,           /* bLength */
  USB_INTERFACE_DESCRIPTOR_TYPE,     /* bDescriptorType */
  0x00,                              /* bInterfaceNumber */
  0x00,                              /* bAlternateSetting */
  0x01,                              /* bNumEndpoints */
  USB_DEVICE_CLASS_HUMAN_INTERFACE,  /* bInterfaceClass */
  HID_SUBCLASS_BOOT,                 /* bInterfaceSubClass */
  HID_PROTOCOL_MOUSE,                 /* bInterfaceProtocol */
  0x00,                               /* iInterface */
/* HID Class Descriptor */
  HID_DESC_SIZE,                     /* bLength */
  HID_HID_DESCRIPTOR_TYPE,           /* bDescriptorType */
  WBVAL(0x0101), /* 1.01 */          /* bcdHID */
  0x00,                              /* bCountryCode */
  0x01,                              /* bNumDescriptors */
  HID_REPORT_DESCRIPTOR_TYPE,        /* bDescriptorType */
  WBVAL(HID_REPORT_DESC_SIZE),       /* wDescriptorLength */
/* Endpoint, HID Interrupt In */
  USB_ENDPOINT_DESC_SIZE,            /* bLength */
  USB_ENDPOINT_DESCRIPTOR_TYPE,      /* bDescriptorType */
  USB_ENDPOINT_IN(1),                /* bEndpointAddress */
  USB_ENDPOINT_TYPE_INTERRUPT,       /* bmAttributes */
  WBVAL(8),                          /* wMaxPacketSize */
  0x0A,          /* 10ms */          /* bInterval */
/* Terminator */
  0                                  /* bLength */
};

Now, when connected to the PC, the Keil MCB1700 board appears as HID-Compliant mouse in Device Manager under Win7, so, I imagine, the descriptor is correct. On USBlyzer the device goes through the GET_DESCRIPTOR and SELECT_CONFIGURATION phases, putting a breakpoint in USB_Configure_Event() function confirms that. Unfortunately nothing happens after, the firmware is supposed to refresh IN report data when GetInReport() function is called at USB Endpoint 1 event. The problem is that this event never happens. In fact, it looks like the host never generates the interrupt condition. I'm missing something but I don't see where exactly to dig. Thanks to all for any eventual advise.

Dimitri