Migrating an SGML File into FrameMaker

I have an SGML file that's based on a DTD that was created using another program. I'd like to migrate the SGML file over to FrameMaker.

I was wondering:

1) How do you convert a DTD to an EDD?

2) How do I then create a file that's based on that EDD?

3) Can an SGML file be somehow imported into FrameMaker?

Thanks,