How to set MEMUSE in check _nt

Dear all,

I’m a newbie of nagios. Excuse me, how to set MEMUSE in check_nt for warning and critical in define command and define service? I did the setting as below , but it’s not work… would any body help? Thanks in advance!

In commands.cfg :
define command{
command_name check_nt_mem
command_line $USER1$/check_nt -H $HOSTADDRESS$ -v MEMUSE -w 50 -c 90
}

In workstation1_nagios2.cfg :
define service{
use generic-service
host_name workstation1.company.com
service_description Memory Usage
check_command check_nt_mem!MEMUSE!-w 50 -c 90
}

Regards,
Henry