Anybody know how to add a data limit for free trial user

HI
my name is steven, from malaysia. i need setup a mobile wifi hotspot, but i have some issue about free trial user.
i use RB951Ui-2HnD & Huawei E367 3g modem for my hotspot system.

now i only can configure the free trial user with uptime limit, uptime reset and user profile under hotspot profile. but i need add a data usage limit 50mb for free trial user.

i see under hotspot user profiles have two setting, Queue & Scripts.
can use this two setting auto add the 50mb usage limit for free trial user??

thank you for your help! :smiley: