radwho and date formatting

Hi I'm using Freeradius to authenticate a bunch of network devices whom all are expected to have a long-term, more or less permanent connection to my network. Any disconnect from the net is considered a deviation from normal operation. Currently I've been using radwho to list status for my devices. Unfortunately radwho only seem to format the date with weekday and hh:mm timestamp. Is there any way I could get a more exact date from radwho or is there other mechanisms I could use to get info on all "live" sessions? ./PerW