uinput dosen't pass HWHEEL event

my user space driver need to input some mouse and keyboard events to kernel, so i create a uinput device in the driver, input events to it, and use application “xev” to check output, all the events i input can be caught except event HWHEEL, ubuntu and red hat don’t have this problem, anybody knows why and how to fix it?

OS version is SLED 11 SP 1&2