Can I keep persistance using Single Signon Cookie?

Two answers:

First, a simple rule that does universal persistence on a cookie only ever present coming from the client would look like this:

 
 rule signon_persist { 
    when HTTP_REQUEST { 
       persist uie [HTTP::cookie ObSSOCookie] 
    } 
 } 
 

Second, Dr.Teeth referred to cookie hash persistence, which is more or less the equivalent to the above. It only performs persistence based on an already present cookie. In your case, you might configure it like:

 
 profile persist signon_persist { 
    mode cookie 
    cookie mode hash 
    cookie name ObSSOCookie 
    cookie hash offset 0 
    cookie hash length 0 
 } 
 

Either of these methods should work fine for persisting the same signon cookie to the same server.