Airport extreme + hub + HDD

I have a new AEBS and want to connect a printer and an external HDD to the usb port.

When the HDD is connected through an unpowered hub it is not detected (a bit strange, since the HDD has its own power supply). But, as recommended, I bought a powered hub and this works - partly. Reading from the disk works, but when writing to the disk it is stuck somewhere in the process. Parts of files are actually written but usually not completed. The disk light doesn't blink anymore but has a constant glow. From then on the disk is not seen anymore and I have to disconnect/reconnect the disk to get it started again.
The HDD is a WD Essential se 1.5 TB (HFS formatted) and works perfectly when connected directly to AEBS without the hub. The hub is Trust branded, USB 2.0 and powered.

Any advice? Before I buy another hub I would like to be confident that it will work...

you can only attach 1 device to the USB port on an Airport Extreme. Unfortunately a USB hub is not one of those things. You can attach either a USB Printer OR USB Hard drive.

That's not what Apple says!

I quote from the official setup guide:

• Connect a USB hub to your AirPort Extreme, and then connect multiple USB devices, such as printers or hard disks. All of the computers on the network have access to those devices.