Your halfway there. Once you import your C4D created .3ds file go to the Swift 3D Material Editor and create a new material. In the material settings under colour and Textures>Pattern, select bitmap and choose the texture map you used for your model in C4D. Adjust any specular/bump settings and then click okay.

Now drag a copy of your material onto your model in the Swift 3D viewport and bang, your UV's should all be intact and display your texture wrapped as it was in C4D. If you are using multiple texture maps in C4D for a particular model, then create a Swift 3D material for each and drag each material onto the objects of your model that each material was original mapped too.