Unable to understand if RTL8191SU works...

Hi there!
Just installed and updated arch.
The problem is with my usb dongle Realtek RTL8191SU...
1) No led blinkink at all...
2) ifconfig and iwconfig show the interface
3) iwlist scan doesn't report any wifi access points (there are A LOT of ap here...mine too!)

What can i check?

Many thanks!

lsusb?

Bus 001 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub
Bus 001 Device 002: ID 0424:9512 Standard Microsystems Corp.
Bus 001 Device 003: ID 0424:ec00 Standard Microsystems Corp.
Bus 001 Device 004: ID 07d1:3303 D-Link System DWA-131 802.11n Wireless N Nano Adapter(rev.A1) [Realtek RTL8192SU]

i have 8192cu nano receiver and the kernel driver never worked for me (could not find anything). i always had to use this pkgbuild: http://aur.archlinux.org/packages.php?ID=49171

i have 8192cu nano receiver and the kernel driver never worked for me (could not find anything). i always had to use this pkgbuild: http://aur.archlinux.org/packages.php?ID=49171

Can you (please) explain how to install this driver and blacklist the other?
Many many thanks!

Ok...updates....
I've just updated with pacman to the latest firmware...
I can do ifconfig wlan0 up and the led now blinks...
BUT:
lsmod:
[root@alarmpi ~]# lsmod
Module Size Used by
ipv6 221660 10
r8712u 125628 0

and if i do iwconfig wlan0 essid "myssid":

Error for wireless request "Set ESSID" (8B1A) :
SET failed on device wlan0 ; Operation not permitted.


Any idea?

How do you get iwconfig working? It doesn't appear to be there on the arch download and pacman -S network-tools doesn't work

I've done a full update - but am rather lost with this distro. pointers would be appreciated.

What I want to do is get lxde and my wifi donge installed and working and to check whether the problem seen on Deb with hubs and wifi exists on this distro.