Hi Gourami,
I was wrong in my previous comment when I double checked it you're correct you do have to add each user seperately. A way around this would be to add all the users you want to grant remote vpn access to in a group ( this is an old link on it that might help you ) and then call on the group from the SRX :
set security dynamic-vpn clients all user-groups "Usergroup name"
