Today, after some sleep, I got the FLdigi published circuit working on the breadboard. Seems I had FLdigi up all the way, but my sound card was only half way up. Operator error! Thanks for your help.
OK congrats, must be, I watched the schematic of which the link was given, and that must do what it is intended for. If not your isolation transformer is not 1:1 and interchanging primary and secondary should work.