[Zope-CMF] new Role in CMF, like a SpecialMember

[cyrille]

hello,

A question about my experience :

I create a local role in CMF Site root :
    - SpecialMember
Because I want to make difference between default CMF Member role.

I created a user with roles : 'SpecialMember' and 'Owner'

If I try to login with that user, login_form come back to login_form 
with ne special message.
This user can't access his folder.

So, I overide CMF Site root security :
    - Role SpecialMember : add security : Set Own Properties

And login is now working : the SpecialMember user can access his folder 
like a normal Member.

so it's working, but I would like more explanation and want to know if 
it is the right way for creating special CMF Site Member ????

thanx for idea, comment, lesson.
Cyrille