Oh! … I found what I was doing wrong … it was a Music Folder issue.
My Firefly “Music Folder” was pointing to “My MusiciTunesiTunes Music”, whereas it needed to be pointing to “My MusiciTunes” (a little higher up in the iTunes folder hierarchy — that’s where the “iTunes Music Library.xml” file is located). Now my Pinaccle SoundBridge sees all of my iTunes music content, including playlists. Everything is working fine, now.
This looks like a common “newbie” error, judging from some of the posts I’ve seen on this forum. Maybe I’ll post a “Getting Started” message on this forum for newbies – that might save some time for people using a configuration like mine (iTunes/Firefly/Win XP/Pinaccle M1001).