hostap and configuration

[capacity77 at tin.it]

my card works in Master mode, if I try to change it with
 
iwconfig wlan0 mode Auto

the message given is

Error for wireless request "Set Mode" (8B06) :
    SET failed on device wlan0 ; Operation not supported.

the hostap modules get loaded everytime I insert the pcmcia card, how can
I assign the linux-wlan-ng driver to the card if I want only to be a client?
Or each time i have to edit the hostap configuration files?
thanx
Dom