Mounting Galaxy S3 internal SD card

[Alex]

Hi,

Just got a new Samsung Galaxy S3 and would like to transfer files
between it and my fc15 box. When I insert the USB cable, it seems to
mount it with a file manager pop-up showing
"SAMSUNG_Android_SPH-L710", but it's otherwise not accessible on the
filesystem.

How was it mounted?

I've found several references to jmtpfs and MTP, but I was previously
able to mount my original Galaxy without any additional software, so
I'd appreciate a better explanation of what's happening.

It seems to show up as a USB device, but I can't access it:

[3791164.746674] scsi 104:0:0:0: Direct-Access     Generic- Multi-Card
      1.00 PQ: 0 ANSI: 0 CCS
[3791164.747120] sd 104:0:0:0: Attached scsi generic sg1 type 0
[3791164.749856] sd 104:0:0:0: [sdb] Attached SCSI removable disk
[root at sage ~]# fdisk -l /dev/sdb
[root at sage ~]#

Ideas greatly appreciated.
Thanks,
Alex