But, I've started a rescue shell and tried:
lspci -nn
01:00.0 Network controller: Realtek Semiconductor Co., Ltd. RTL8187SE Wireless LAN Controller (rev 22)
03:00.0 Ethernet controller: Atheros Communications AR8121/AR8113/AR8114 Gigabit or Fast Ethernet (rev b0)
So... Both of my interfaces are detected. But when I start the network
configuration, it configures eth0, without asking me to choose between
the 2 network cards.
The lspci command gives what the kernel has detected, not what the
installer has found when it runs the detecting the network hardware
option. It looks like d-i is misbehaving and does not pick up on the
wireless interface.
In a console
cat /var/log/syslog | grep wlan