there is 2 ways to do it that I know of but am not sure exactly the method.
you can add a line to the fpe or use a script with lua
adding a line to the fpe is faster but has drawbacks, it effects every model of that named type, ie combat soldier from the engine stock media would all be bigger not just 1 model..
making a script might be alittle slower if you don't know scripting, but only effects the models you add it to I think, but am not 100% certain on that myself as I have not tested it yet this way.
both ways are not exactly in editor, not like a gizmo would scale in live time. best we can do at moment though I think.
evga GeForce gtx 750 ti boost2.0 2gb gddr5. win 8.1 quad core 4gb ram.