Spring RTS Engine

Does anyone know how to do this in lua without completely rewriting all the commands and simulating them in lua?

What exactly are you trying to do? A crude paint image might illustrate it well.

Layout handler.

For Tower Defense?

Should be able to hook/remove commands from the build menu with the layout handler, then make lua buttons in another area with equivalent functionality (you can send commands like attack etc with custom buttons).

A recent CA version had half the buttons removed with a custom layout handler.