The HP Bluetooth keyboard installed easily on my Axim X50v.
You will need to download & install the lastest driver from HP onto the Axim. The driver installation creates a program that you'll need to use to recognize the keyboard (the Axim's Bluetooth pairing wizard won't recognize the keyboard).

Also, you'll need to enter "0000" when prompted to authenticate the keyboard. Hope this helps.
Anyone have suggestions on a Bluetooth mouse to go with the Axim X50v?