New field Fieldgroup creation (duplicate)

Based on www.flexicontent.org/documentation/faq/7...-new-field-type.html , I try to duplicate a field Fielgroup in order to custom it.

I can create the new Fieldgroup (and the new Fields) [everytihng look ok in the DB], but I can't list (display in the row)) them in backend. I list all the fields, except the new ones, and the backend template is broken.

I can't findout what goes wrong.

Any ideas ? Thanks for your help.