use curl to call restapi

hi guys :

I used RESTAPI to create the AFM policy , but VIP cant call this policy.

This is my code and related code error:

[root@localhost /]# curl -sk -u 'admin:admin' -H "Content-Type:application/json" -X PUT https://10.1.10.66/mgmt/tm/ltm/virtual/ -d '{"name":"vs_ddos","fwEnforcedPolicy":"policy_test"}'

{"code":403,"message":"Operation is not supported on component /ltm/virtual.","errorStack":[],"apiError":1}