WEP & DHCP: Works with one card, not the other

[Ulrich Plate]

I have two WLAN cards, an antique Orinoco Silver that only supports
40-bit-encryption, and a Netgear MA401. The Orinoco card works just fine
with ifconfig_wi0="DHCP" in rc.conf and an additional start_if.wi0 that
reads

#!/bin/sh
/sbin/ifconfig ssid XXXXX wepmode on weptxkey 3 wepkey 1:XXXXX 2:XXXXX 3:XXXXX 4:XXXXX 

but when I boot with the Netgear card in the slot, the exact same setup
doesn't produce the expected result. The instructions from start_if.wi0
are clearly accepted, but DHCP fails to obtain an IP address. I suspect
the crypto portion to be at fault because manually assigning an IP
address and adding a default route doesn't get the card online,
either... man 8 ifconfig recommends hex keys because different drivers
handle keys differently, could that be the reason why it doesn't work? 

Much obliged for any ideas you might have
Ulrich Plate