Today I’ve seen the code in CalendarProfile Form and if you put $SignatureOptionEnabled=1 in your notes.ini file it enables the old options besides the new rich text signature (text, html file, rich text).It mantains the old values in the profile (the html file path). You only need to put the varible in the notes.ini file, it’s not necessary to re-save the mail preferences.
We need some more people requesting this lost feature in the next version. IBM support told me that there is a improvement proposal SPR # ATHS7KP449 APAR: LO37562 for this.