microsoft wireless mouse 5000 middle button intermittent or not working.

I have just purchased a combination Microsoft wireless keyboard with mouse 5000.  I have configured the scroll wheel button (using the Microsoft keyboard and mouse utility) to perform "Middle Click" instead of "Flip". Even so on several applications the pressing the mouse wheel down does either nothing or is highly intermittent. I have a program (Eagle Cad) which uses the middle wheel press to allow scrolling. It works with a logitech mouse. But I cannot get it to work with the MS mouse. I have used a website which informs the user of what mouse button has been clicked using the browser and it only intermittently sees the middle mouse button press. The other buttons seem to work.

I could blame it on the mouse hardware itself I suppose since it seems somewhat intermittent but then I cannot explain why the cad software does not respond at all. I can configure the right mouse button to be "middle click" and that works in my cad program. I just cannot get the actual scroll button to work that way. Also if I configure the scroll button to be the "Right Click" it works intermittently in windows as a right click.

Anyone else have this problem (or better yet a solution!) before I return it? My gut feeling is that when I exchange it I will find the exact same problem with the new one but I suppose I must go through the motions.

Also I have uninstalled the Intellipoint software and the base mouse driver has no configuration parameters for the middle button (and it does not work).

Any help appreciated.

UPDATE:

1. I verified the system works fine with another brand of wireless mouse which also has a center roller button (Logitech)
2. I exchanged the MS Keyboard/mouse for an identical one to make sure it was not a fault of the actual hardware.
3. I verified that IF I pressed the center button in a specific manner, taking care not to let it roll in any way, that I could 60% of the time generate the middle button press event.

The roller on this mouse has no detent and so pressing it down without it rolling at all is VERY difficult. My solution was to not use the middle press function at all. I reprogrammed the side buttons to perform that function (thus demonstrating that the middle click event can be generated consistently by every button BUT the middle roller button. I have concluded it is a mechanical design flaw.  Disappointing though not to be able to use it as specified.