Convert Citrix Netscaler rule to F5 Persistence Profile or iRule

I'm not sure I have the nuances of the Citrix rule down pat, but I suspect this is what you need with a Universal persistence profile (see http://support.f5.com/kb/en-us/solutions/public/7000/300/sol7392.html);-

when HTTP_RESPONSE {
    if { [HTTP::cookie exists "GreenwaySession"] } {
        persist add uie [HTTP::cookie "GreenwaySession"]
    }
}
when HTTP_REQUEST {
    if { [HTTP::cookie exists "GreenwaySession"] } {
        persist uie [HTTP::cookie "GreenwaySession"]
    }
}