HID on USB composite device working?

I’m currently trying to connect an Arduino to a raspberry pi 2. The Arduino has been programmed to be a USB keyboard, and works in this role on Windows on PC and Linux on the same raspberry pi 2. Under RISC OS, it does not work as a keyboard.

Does anyone know a way this could be made to work on RISC OS?

The Arduino reports itself as a composite USB device that has 3 sub devices, one of which is HID.

Here is a screenshot and the details as reported by !USBInfo.

   Device: 6
      DeviceFS  : USB6
      USB spec  : 2.00
      Class     : 0     (Defined at Interface level)
      Subclass  : 0     
      Protocol  : 0     
      MaxPacket : 64
      Vendor    : 2341  
      Product   : 8036  
      Release   : 1.00
      Speed     : Full speed (12 Mb/s)
      NumConfigs: 1
      
      Config: 1
         MaxPower  : 500 mA
         Attributes: (Remote Wakeup) 
         Interfaces: 3
            
            > Report=11 Length=8
            > 08 0b 00 02 02 02 01 00 
         
         Interface: 0
         Alternate: 0
            Class     : 2     Communications
            Subclass  : 2     Abstract (modem)
            Protocol  : 0     None
            Endpoints : 1
            
            > Report=36 Length=5
            > 05 24 00 10 01 
            
            > Report=36 Length=5
            > 05 24 01 01 01 
            
            > Report=36 Length=4
            > 04 24 02 06 
            
            > Report=36 Length=5
            > 05 24 06 00 01 
            
            Endpoint: 1
               Direction : IN
               Transfer  : Interrupt
               MaxPacket : 16
               Interval  : 64 ms
         
         Interface: 1
         Alternate: 0
            Class     : 10    CDC Data
            Subclass  : 0     Unused
            Protocol  : 0     00
            Endpoints : 2
            
            Endpoint: 2
               Direction : OUT
               Transfer  : Bulk
               MaxPacket : 64
               Interval  : -
            
            Endpoint: 3
               Direction : IN
               Transfer  : Bulk
               MaxPacket : 64
               Interval  : -
         
         Interface: 2
         Alternate: 0
            Class     : 3     Human Interface Device
            Subclass  : 0     No Subclass
            Protocol  : 0     None
            Endpoints : 1
            
            HID Descriptors available:
               Report (type 0x22, 47 bytes)
            
            Endpoint: 4
               Direction : IN
               Transfer  : Interrupt
               MaxPacket : 64
               Interval  : 1 ms