Character Creator 3 is a 3D product using 3D meshes for characters whereas Cartoon Animator 4 uses flat 2D images for characters. Because of the major difference there is not a direct output from CC3 to CTA4.
However, what you can do is render images of your character in CC3 at the appropriate angles, and then use the images as the source to create a character in CTA4. The process for doing this is the same as for creating any new G3 character in Cartoon Animator 4.
If you need help creating characters from images in CTA4, please let me know if you have the Pro or Pipeline version and I'll point you to some tutorials to help you get started.