mouse and extra buttons

Hello,

I need help with mouse having extra buttons. I have googled a little
bit around and have not found working solution. I think I was doing
everything all right. Maybe somebody already have had similar problem
and have idea what can be done to fix it.

I have tried various combinations but have not succeded to make extra
buttons work. Standard buttons and wheel works perfect. Here is what I
get when I attach mouse:

ums0: Cellink Co., LTD. Wireless RF Mouse, rev 1.10/0.01, addr 2, iclass 3/1
ums0: 6 buttons and Z dir.

I try `cat /dev/ums0` and get something when I click buttons 1, 2, 3
and scrooling wheel and I get nothing when I try to use extra buttons.
I think problem is somewhere in ums. Have looked in it (ums.c) but
have no idea where to look and how to work with it (without
recompiliing the whole kernel).

My system is:
FreeBSD 6.0-STABLE

--
Dalius