OS X Automount Notes
Below is one approach to configuring an AFP auto mount. You should carry out the following commands as root. Note that storing passwords like this is not advised due to security implications.
First create a directory for the auto mount(s).
mkdir /Volumes/automounts
Append the line below to the following file /etc/auto_master.
/Volumes/automounts auto_custom_automounts
Create a file /etc/auto_custom_automounts and add the following line.
automount_name -fstype=afp afp://username:password@server.local/mount_point_name
You can set 'automount_name' to be the name of the mount point within /Volumes/automounts.
Next restrict the permissions on this new file
chmod 600 /etc/auto_custom_automounts
Finally, reboot your system or issue the following command.
sudo automount -vc