Hostapd and madwifi interaction

[Stefano Paris]

Hi 
i'm an University researcher, working with wireless devices. I employ
hostapd with madwifi drivers, since i use atheros based cards, and i
have a couple of doubts regarding the interaction between the drivers
and hostapd (0.5.8) itself. 
In particular, do hostapd configurations override madwifi
configurations? Some examples: 
- if i set up a wep key with the "iwconfig ath0 key s:goofy" command
(i.e. using the madwifi drivers), should i also add such "goofy" key to
the hostapd.conf file? what happens if i don't? and if i do, will i be
able to change the key without restarting the hostapd daemon (i ask this
since i'm wondering about periodically changing the wep key for security
reasons, because I'm using the madwifi ad-hoc mode that seems to support
only the wep security framework)? 
- if i tell hostapd.conf that channel=60 (therefore hw_mode=a), am i
allowed to change the channel through the wireless tools without
restarting hostapd? 

Moreover, does hostapd keep an "associated station list" separate from
the madwifi "associated station list"? I did set ap_max_inactivity=30 in
order to have the ap consider gone a station that does not send or ack
any frame for 30 seconds; then i performed a mobility test, moving
(through the iwconfig ath0 ap new_mac_ap) the station from an ap to a
new_ap, both of which running hostapd, and by observing the madwifi
"associated stations list" on the old ap (through the "watch -n1
wlanconfig ath0 list sta" command) i didn't see it vanish from the old
ap. I actually saw it for a long period of time (around 5 minutes,
maybe) associated to both aps.... Is it an hostapd configuration
problem?

Thanks in advance for your kind answers 
Best Regards
Stefano Paris