Creating a Mirror

Detach mirror

In 3ds Max, detach the mirror surface from the rest of the geometry.

Unwrap UV

In 3ds Max, the mirror surface geometry requires a new UV Unwrap.
The unwrap needs to occupy the full 0 to 1 UV space.

Export the model

Still in 3ds Max, export the model to .DAE (OpenCOLLADA) file and load it into the Graphics Gallery.

Apply new material/texture

In Vortex Studio Editor, apply a new material to the mirror surface and apply a texture of your choosing to the Emission slot.

Load the Graphics Gallery

Create a new mechanism and load the Graphics Gallery from earlier.

Create a mirror extension

Select Cameras in the Toolbox, and then select Mirror as the name.
Double-click it or drag it to the desired location in the Explorer panel to add it.

Load texture

Load the exact texture into the mechanism (the same texture you previously loaded into the Graphics Gallery).

Select texture target

Select the mirror extension in the Explorer panel. In its resulting Properties panel, select the texture that you imported in the previous step as the Texture Target.

Move mirror

At this point, you should have a working mirror.
You can move the mirror around the viewport to change what appears reflected on the mirror geometry.