Maybe I am to late with my response but somebody else can do something with this answer maybe.
I'm using mandrake 10.0, I also do have an evil fast 800, and yes I'm also tiscali(.be) member . Well I almost had the same problem as you did, but with me the driver from Sagem wouldn't work because he was not suited for a 2.6 kernel. After some months of searching on the internet I found a driver which is suitable for the fast 800 and for a 2.4 and a 2.6 kernel. I installed from the shell as root and in five minutes my connection was fixed (this was a week ago).
And now you want to know were to find this driver, well here it is: http://www.eagle-usb.org
ok, it is in french but choose to download the Eagle-Usb-1.9.9 and then you can choose for the english version. To install just follow the steps they tell you and it will be configured in no time without manipulating in some files.
Hope you can still do something with it...............