Finally I successfully managed to log into the cisco switch (thanks to your help) using freeradius.
Now I want that the radius users can directly enter into enable mode of the cisco device. I set this in the users file
test Auth-Type := Local, User-Password == "test"
Cisco-AVPair = "shell:priv-lvl=15"
but it doesn't work, the user "test" log into the cisco as unpriviledged.
Is there something missing in the config?