My e-mail address is in the config.txt file of all my assets on the DLS. User ID 68213: - but you may not need to send me the file, you are so close to getting the scaling thing to work. Just read below and if you still have trouble, then send me the files.
When I refer to the 'stack' in gmax, do you know what I mean? It's in the little panel to the left of screen where you see menu trees such as "Editable Mesh" and so forth.
Select your object. Just above the stack panel there is a dropdown list called "Modifiers". Open that and scroll right down to the modifier called "XForm". Click it to add an XForm modifier to your stack.
Then click on the little + sign next to "XForm" to expand that modifier menu, and you should see the level called "Gizmo". Select that before you do any re-scaling of your object.
You know where the uniform scale button is on the toolbar. Put your mouse cursor over it, left-click and hold it down. Several different types of scaling buttons will roll out, including the non-uniform scale button you want (the middle one of 3). Keep holding down the left-mouse and scroll down to select it. Release it and confirm the non-uniform scale button is highlighted (ie. active).
Now go to your object - it should have a yellow box around it indicating the XForm modifier has been applied. Mouse over the axis tripod and highlight the direction you want to use - X, Y or Z. The cursor should have changed to a black/white mini version of the non-uniform scale button when you have correctly highlighted a direction.
Left click and move your mouse up or down to expand or compress your object in the direction you chose.
Tip: it's better to do scaling in one of the orthogonal viewports rather than in the perspective viewport.
I hope this is sufficient to show you the way. If not, send the files.
~ Deane