I am woking with Acrobat Pro 10.1.7 on mac OS 10.6.8.
I made a new ink signature by scanning my signture and importing it in to Acrobat > Preferences > Security > New. That worked and I can see that signature under Preferences. When I try to sign a document, however, I cannot find that new signature when I go to Tools Panel > Sign and Certify > Sign Document. Why not?
Tools Panel > Sign and Certify > Sign Document is for PKI-based (certificate) signatures, not for image-based signatures. What you did, you specified appearance for your PKI-based signatures. What you want to do is to use Comments Panel->Add stamp->Show Stamps Pallete. Select "Sign Here" and "Import" to import the image of your signature. Then use Comments Panel->Add stamp->Sign Here to apply your signature as a stamp. Keep in mind that this signature is not a PKI-based signature that has support behind it. It is just an image that you add to PDF.