FT won't recognize the edges of the data. There are things that you can do to teach it about the edges of the data, though, such importing your world data, using Tools>>Action>>Burn In To Surface, the using a selection that represents your map area to restore the roughness to areas outside your map area (Tools>>Global Set>>Roughness to 1). You can use any of the FT tools from that point to adjust things. You'll need to do manual blending across the boundaries of your image block , for example, to make them less obvious.

It's probably easier to just load your CC3 image as an Image Overlay in FT and manually paint your outlines, though.