For both my ndiswrapped acx111-chipset pci card and my native bcm43xx-chipset pcmcia card I use -Dwext and it works fine. I also use wifi-rader to actually establish the connection. My network is not broadcast, does not use dhcp, and uses WPA. I create a wifi-rader profile with the ssid name, managed, auto channel, key left blank, wpa option left off [I DO use WPA], specify local ip, netmask, domain, dns1.
The way I typically start my wireless network is like this (from boot):
ifconfig wlan0 up
wpa_supplicant -Bw -Dwext -iwlan0 -c/etc/wpa_supplicant.conf
Then I run wifi-radar and select my preconfigured profile and connect to it (of course adjust the interface name to match yours).