I'm almost in the same situation and I just need the USB filter to work to see my iphone.... could you please show the settings or a screenshot of the USB filter that you modified in VirtualBox? That would really be great!! I've been spending the last hours just trying to get a USB device to work!
By the way, for the sound, there's a zip for the driver, I believe I found it in VirtualBox forums.
Here you go - it's in portuguese, but the layout is the same. This case is for the iPad, maybe for the iPhone you can change the title
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