Since the MultiDock's USB hub doesn't seem to be suitable for this project, it'll have to come out. I've done a bit of exploratory rummaging around inside it. As long as you have a T20 "security" torx bit (with a hole in the middle), the MultiDock is very easy to get into. Simply unscrew the back plate, then remove three screws and slide out the device tray, and the electronics are exposed. (Photos will be added soon - I need more light!)

The internal construction consists of a metal-cased power supply, a large flat PCB which holds the USB hub controllers (3x SMSC/Microchip USB2514B) and a few other components, and a series of 10 vertically-mounted boards with the USB sockets and status LEDs on them.

Each of the 10 vertical boards is connected to the main board by a short USB mini-B male to mini-B male contains a surprising amount of circuitry, including:

• 1x PIC16F616 MCU
• 1x TI TPS2511 USB Dedicated Charging Port Controller
• 1x TI TS3USB221A 2-port USB multiplexer/switch

I haven't reverse engineered the whole thing yet (far from it), but so far I've been able to determine that the TS3USB221A is used to switch the USB port between the USB2514B hub and the TPS2511 dedicated charging port (DCP) controller. I'm guessing that the PIC is deciding whether to switch it to the hub or DCP controller, and that my compatibility issues are being caused by it connecting most of my devices to the DCP rather than the hub. I'm not currently sure how it decides - but may be able to figure it out from a closer inspection and/or a bit of probing. A minor hardware hack to tie the TS3USB221A's port selection pin either high or low (depending on which port is which) may also be an option, if I can find a safe/easy connection point. If I can force the ports to hub mode, it'll still remain to be seen whether that allows the devices to draw sufficient current to charge (or at least maintain, rather than draining the battery).