Application.cfc

Is it possible to write a value to (say) the CLIENT scope using onSessionEnd (or is the "session" already over and thus the "client" no longer in existence? (example code to follow). For what it is worth, the Ben Forta WACK has an example that writes a duration to a log file but this does not necessarily have a relationship to the specific client (ie it just records the duration of each session but does not say which is the associated "client"). As always, thanks in advance.

<!--- Runs when session ends --->
<cffunction name="onSessionEnd" returnType="void" output="false">
<cfargument name="theSession" type="struct" required="true">
<cfset var duration = dateDiff("n",arguments.theSession.created,now())>
<cfset CLIENT.duration = #duration#>
</cffunction>