Need more details about Nessus to perform local security checks on top of SSH

I did every steps according to the article: Using Nessus to perform local 
security checks on top of SSH.htm. But it didn't work. 
The Nessusd running machine's IP is 192.168.1.6, the target's IP is 
192.168.1.8. 
First: in 192.168.1.6
su nessus
ssh-keygen -t dsa
It will generate the keys: id_dsa and id_dsa.pub in /home/nessus/.ssh
Second: in 192.168.1.8
add a user named nessus, and set the nessus's password * use vipw. copy the 
id_dsa.pub from 192.168.1.6 to the 192.168.1.8 
directory:/home/nessus/.ssh/authorized_keys2. Indeed when I failed I tried 
other names like:authorized_keys and authorized_keys21
Last: set the ssh's setting like username: nessus, public key 
/home/nessus/.ssh/id_dsa.pub, private key: /home/nessus/.ssh/id_dsa. etc. in 
client nessus. 
When I scan 192.168.1.6, it seems work, I can see some information like: enable 
local security check in result. But to 192.168.1.8, it seems that the plugin 
ssh_get_info.nasl didn't work. can't see any information in result about local 
security check.
I use command: 
ssh -l nessus 192.168.1.8
in 192.168.1.6. It will succeed without need any password, seems the dsa public 
key is working.
So I'm confused. Is there anyone could give me more details about this? Any 
problems in my steps?
Any suggestions will be appreciated.
The OS is Redhat 9, nessus version is 2.2.2a

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