Hi cinfo,
There must be an incompatibility issue with the wireless card and bm2lts. The wifi works fine with old AVG2 image 12.12.1.
My wireless card mini pci-e card :
Ethernet controller: Qualcomm Atheros AR242x / AR542x Wireless Network Adapter (PCI-Express) (rev 01)
My /etc/networks/interfaces :
# This file describes the network interfaces available on your system
# and how to activate them. For more information, see interfaces(5).
#
# WARNING: This file is auto-generated by the ReelBox setup, so you
# should not edit it manually. Use the setup menu instead.
#
# The loopback network interface
auto lo
iface lo inet loopback
address 127.0.0.1
netmask 255.0.0.0
auto eth0
iface eth0 inet dhcp
auto eth1
iface eth1 inet dhcp
auto eth2
iface eth2 inet dhcp
auto wlan0
iface wlan0 inet dhcp
wpa-ssid MOVISTAR_7652
WPA-PSK 12345678
auto eth0.2
inet dhcp iface eth0.2
-------------------------------------------------
As soon as i save this, AVG2 does not work anymore !
You have to unplug from the main switch and connect ethernet cable.
The script also says that it should not be modified manually because AVG2 auto generates this.
I think this is also a reason wifi is not working.
Ok , next week i will have Fritz and hopefully wifi . 
Thanks again for your time and trouble.