I have a Trust Direct Access II keyboard and all the multimedia keys don't work
fine. I have modified the /etc/X11/xkb/symbols/inet file to solve the problem
and now it work perfectly. The lines that i have writed are:

partial alphanumeric_keys
xkb_symbols "trustda" {
    name[Group1]= "Trust Direct Access II Keyboard";

    key <I5E>	{	[ XF86PowerOff		]	};
    key <I5F>	{	[ XF86Standby		]	};
    key <I6C>	{	[ XF86Mail		]	};
    key <I65>	{	[ XF86Search		]	};
    key <I66>	{	[ XF86Favorites		]	};
    key <I32>	{	[ XF86WWW		]	};
    key <I22>	{	[ XF86AudioPlay, XF86AudioPause ] };
    key <I24>	{	[ XF86AudioStop		]	};
    key <I20>	{	[ XF86AudioMute		]	};
    key <I10>	{	[ XF86AudioPrev		]	};
    key <I19>	{	[ XF86AudioNext		]	};
    key <I30>	{	[ XF86AudioLowerVolume	]	};
    key <I2E>	{	[ XF86AudioRaiseVolume	]	};
};

Thanx