There is a third party USB cable that will trickle charge the Z as well. The supplied sync cable does not charge without the charger.
The AC charger will work directly into the Z. You do not have use the sync cable.
English roms and flash instructions are available here on the Zaurus user group site. My guess would be for you to try the cacko rom for the 860.
do u mean the usb sync cable can charge th C860? does the AC adaptor need to be connected to the usb sync cable as shown in the manual?