You can create a new template for it. To do that use:
- Close LDCad
- Go into "%appdata%\LDCad\templates\path"
- Copy rubberBandSquare.ldr
- Rename it to something appropriate
- Open LDCad and locate the band copy in the template bin.
- Edit the template directly to make it use bezier etc.
- (optional) edit its header / description.
- You can now use that template in any other model.