Change the user and group of SD card automount on Debian

Hello,

I’m using the Debian distribution “BeagleBoard.org BeagleBone Debian Image 2014-05-14”.
When I’m inserting an empty SD card into the micro-SD slot of the Beagle Bone Black, the SD card is mounted in /media/PARTITION_LABEL with the owner debian:admin.

Where can I change the user:group and umask of the user owning the automounted SD card?

The udisks-daemon seems to be involved in automounting, but I couldn’t find any configuration file where to specify the mount options.

Regards,
Stefan.

p.s.: Sorry for any duplicate posting. I posted a similar message some hours ago, but it didn’t show up in the forum. I couldn’t find any notes on moderation before a post shows up in the group so I thought my posting got lost somehow…