There is no current option to add rings or ankle bracelets using the character editor.
If you really want to do this and look how you want it to, I suggest you go the same route I did when I wanted to add belly button jewelry to my custom girls; That would be to create the jewelry in transparent PNG form and add them to your girl's custom texture files as new visible layers.
Check out my post on that topic here:
http://www.sexsim.com/forum/index.php/topic,861.0.htmlDownload my jewelry there and follow the instructions to use them. Play around with it for a while and I think you will get some good ideas on doing what you want with your idea for the wedding ring and bracelet(very cool idea by the way, hope you will post some pics when you are finished with it).
Hope that helps you out. If you have any other questions feel free to ask as I'm more than happy to help out here. Cheers and good luck!