aux/wpa doesnt need to be restarted really. it uses factotum to derive the psk using the current essid read from the wifi drivers ifstats file. so to switch essid's you can just set essid with echo essid XXXX > /net/etherX/clone or the ctl file. (note, you can read the ifstats file to see the list of ap's it found).
if you run a key prompter like aux/fgui, it should prompt for the password. otherwise you need to have the key in factotum for that essid like: key proto=wpapsk role=client essid=XXX !password=YYY -- cinap
