adding user-name to post-proxy logs

hi - i'm logging the pre-proxy and post-proxy logs. this works fine. the proxy-logs show the user-name (and password attribute) and that is fine. however the post-proxy logs don't contain the user-name because the reply from the backend radius server doesn't necessarily send the username as an attribute in the reply packet. since the state must be maintained in the freeradius proxy - is it possible to add it to the logs so that troubleshooting is easier? currently i have to match the timestamps. if i wrote the pre- and post- proxy logs to the same file i am guessing that the send-receive won't neccesarily be consecutive in the logs (like they are in other single-threaded servers!) tariq