[Samba] attrib dos

[luca.work]

 I have a problem for modification attributes dos
 I have shaped directory private, I only approach you and can modify
 attributes MSDOS THROUGH WINDOWS.
 
 Configuration:
 --------------------
 [luca]
       path=/home/luca
       valid users = luca
       writeable=yes
;     force create mode = 750
 ;     force directory mode = 750
 
---------------------------------------
 
 Now I render publishes mine directory.  I want that all can access:
 --------------------------
 [pubblica]
       path=/pubblica
       browseable =yes
       public= yes
       writeable=yes
       force create mode = 777
       force directory mode = 777
 ---------------------------------
 
 
 I have had to set up:
 - force created mode = 777 -
 - force directory mode = 777
 
 in order to allow all to modify and to cancel. Now the attributes cannot
 piu' be modified.
 
 why?
 
 Thanks Luca