In edgy 6.10 beta gparted does not see all the available disks

Binary package hint: gparted

I have started the Edgy 6.10 beta ISO cdrom with the intention to install a test image of the OS on my external USB disk (200GB).
After booting up, with the external USB disk powered up and connected to the system, I started the installation program from the desktop. As soon as I have reached the selection of the install media I decided to perform the partition manually (having already other partitions on my external USB disk). This lead to the start of the gparted program.
At that point I tried to select the second external disk on gparted but in the upper right hard disk device selection widget (of gparted) only one disk was available (the default internal one: /dev/sda).
Just to be sure that the external USB was correctly connected and available to the system I opened up the terminal and performed a "sudo fdisk -l" command and the external disk was visible with all the related partitions. As a first attempt to understand the reason behind this behaviour I tried to see if the problem was really due to gparted I tried to see the gparted invocation command but I did not find anything relevant in this context.

Regards
Franco Fiorese