tsql - sql server agent proxy account -

i trying use proxy account non sysadmin grant them exec permission on xp_cmdshell. did is:

use [master] go create credential [proxyaccount] identity = n'domain\user', secret = n'password' go use [master] go create credential [proxyaccount] identity = n'domain\user', secret = n'password' go  use [msdb] go exec msdb.dbo.sp_add_proxy @proxy_name=n'myproxy',@credential_name=n'proxyaccount',                 @enabled=1 go exec msdb.dbo.sp_grant_proxy_to_subsystem @proxy_name=n'myproxy', @subsystem_id=2   go exec msdb.dbo.sp_grant_proxy_to_subsystem @proxy_name=n'myproxy', @subsystem_id=3 go exec msdb.dbo.sp_grant_proxy_to_subsystem @proxy_name=n'myproxy', @subsystem_id=11 go 

but still when user tries do

xp_cmdshell 'dir c:' 

it gives following error:

msg 229, level 14, state 5, procedure xp_cmdshell, line 1 execute permission denied on object 'xp_cmdshell', database 'mssqlsystemresource', schema 'sys'. 

anyone knows else should doing? login has connect permission server.

thanks in advance

you shoud use

exec sp_xp_cmdshell_proxy_account 'domain\user', 'password'; 

instead. not 100% sure think xp_cmdshell explicitly looks proxy account called ##xp_cmdshell_proxy_account## - stired procedure above create you.