I've seen that with html files you save a "xxx_data_and_timetable.fet" file.
In this xml file, you save
<Time_Constraints_List> element which contains many <ConstraintActivityPreferredStartingTime>.
These <ConstraintActivityPreferredStartingTime> elements are the generated timetable data (Activity_Id, Preferred_Day, Preferred_Hour).
So, you could add an option (for example autosave) saving each generated timetable with a unique name (for example name_year_month_day_hour_minute.fet)
This file could easily be loaded from a user just to be able to preview the generated timetable inside FET.
PS: Sorry for my poor English Language !!
OK, I think I'll add this in the TODO. But I don't know when and if it will be done.
Thank you for the suggestion!