Aruba Tacacs+ Authentication

Hi all,

Currently I'm trying to authenticate ARuba switch to LDAP server by using TACACS+.
I have successfully do the AAA with Cisco Switch. But in Aruba, I read that I need to add some VSA in the config file. I have tried, no error, but the authentication won't work.
/**default/
group = Management {
default service = permit
service = shell {
set priv-lvl = 15
default attribute = permit
default cmd = permit
}
/**Added/
service = shell {
set protocol = ip
set Aruba-Admin-Role = root
default attribute = permit
#default cmd = permit
}/**/
}

Please help. Thank you