Bukkit

so I have this command to withdraw a variable amount of coins with custom value as separate items (for use on trading plugin):

batch_withdraw:

command: /bwithdraw
type: RUN_COMMAND_TASK
runcmd:

- '/withdraw $arg1'

tab_completer:

- 1
- 10
- 100
- 1000

required_args: 2
task_run_immediately: true
task_repeat_every_sec: -1
task_run_n_times: $arg2
task_run_when_offline: true
task_show_debug: false
register: true

then I try:

/bwithdraw 1 10

and I get this error:

Not enough arguments... You typed (0/2)

BUT If change $arg2 with $arg1 and replace $arg2 with a number in runcmd then it works, so it seems that arguments in runcmd within a RUN_COMMAND_TASK type command don't work... or am I doing something wrong?