That's impressive. Care to give us a tutorial?
It'll have to be very brief.... I'm not great at tutorials!
Open the image in Viveza.
Place a control point in the middle of one of the darker grey areas.
Adjust the size of the control point (using the top slider on the control point itself) so it roughly fits the grey area.
Whack the brightness of the control point up to max 100%.
Copy the control point by holding ALT then hold left click and drag the mouse, this gives a duplicate of the control point you've just made. Drag the copied point to another grey area... accuracy isn't that important.
Repeat the above until you have covered all of the grey bits with max brightness control points.
Now add a NEW control point to one of the green objects and resize to cover most of the green bits of that area (this will be a NEGATIVE control point to counteract any of the brightness increases from the other ones).
Copy the negative control point as necessary to cover all of the green objects.
Click 'OK' to save and take you back to your host app (e.g.. Photoshop)
That should pretty much do it, the 100% brightness increase should only affect the grey areas thus doing away with any time consuming (and less accurate) masking. Whole process can be repeated if necessary to get the background completely white.
It probably sounds more complicated than it is, it really does take just a few seconds once you're used to it.
This is, of course, a very simple application of Viveza, try it on a more complex image like a landscape or something and see how a control point on something like an area of sky for example can affect local areas of the image dramatically and easily... I really hope it's not discontinued any time soon.