User name case insensitivity

[Luveh Keraph]

I would like for my FreeRADIUS 3.0.20 server to match user names to be
authenticated in a case-insensitive way. To that effect, I changed the
contents of /etc/raddb/mods-enabled/sradutmp as follows:

radutmp sradutmp {
    filename = ${logdir}/sradutmp
    case_sensitive = "no"
    permissions = 0644
   caller_id = "no"
}

When I launch the FreeRADIUS server with -sfXx in the resulting traces I
can see that the module above has been loaded, and that the case_sensitive
attribute is indeed set to "no". However, the FreeRADIUS server remains
user name case-sensitive. What am I misunderstanding here?