Users cannot format USB and other devices

Hello.

User without privileges cannot format devices in a Windows XP systems. 

I setup the security policy ("Devices: Allowed to format and eject removable media") to Administrators and Interactive Users. Also, I check the its corresponding value in the regedit (allocatedasd to 2) but it does not work.

Any suggestions?.

Thanks a lot.

Regards.

Ric.