logitech mouseManPlus and fourth button: how to make it work?

[Erik Steffl <steffl@bigfoot.com>]

  Q:

  is there any way to get the fourth button (on the side of the logitech
mouseMan with wheel) working? It does not work at all - not even with
xev.

  I have:

	logitech cordless mouseMan wheel mouse (4 buttons & wheel)
	XFree86 Version 4.0.3

  here's what works and how (so far):

  MouseManPlusPS/2	buttons 123 are working
  plain PS/2		buttons 123 are working
  IMPS/2		buttons 123 and wheel are working

  so IMPS/2 is almost pefect, only thing not working is the side button.

  here's the relevant part of XF86Config-4:

Section "InputDevice"
        Identifier      "Logitech"
        Driver          "mouse"
        Option          "CorePointer"
        # Option                "Protocol"             
"MouseManPlusPS/2"
        Option          "Protocol"              "IMPS/2"
        # works too: Option             "Protocol"              "PS/2"
        Option          "Device"                "/dev/psaux"
        Option          "Emulate3Buttons"       "false"
        Option          "Buttons"               "6"
        Option          "ZAxisMapping"          "4 5"
EndSection

  btw I've read the README.mouse and debian-user but haven't found
answer (that would work, the settings in X docs for mouseMan+ do not
work with mouseMan wheel)

  TIA

	erik