Can The Audiobook Conversion Feature Be Used To Convert Other Digital Files (E.g. Mp3 Files I Already Have) To An Audiobook Format?

[progman]

Hi, I am interested to see if I can take existing files on my hard drive and load those into Toast somehow and use the Audiobook Conversion feature, so that I can have one big file in iTunes under Audiobooks with all the chapter markings and tags in there. Is there a way to do this with existing digital files like existing mp3 files? Obviously I could burn those files to a disc as CD Audio with id3 tags, then insert that burned disc into the drive and let Toast do the Audiobook conversion, but it would be nice if I didn't have to do this extra step.