That's a nice addition to the method I suggested above, thank you.
I'm sorry, I understand that this may not be convenient, but our team is working on this.

Our team received reports about this issue, it will be fixed in future versions.
Meanwhile, you can try this workaround: use any preferred image editor to create a PNG file with your text on a transparent background. Then add this PNG file to a slide in SmartSHOW 3D. It should look fine.