Annoying "Variable ... will not stay shared" messages

Dear all,

Is there a way to suppress messages that sometimes pop up on CPAN
modules when running as "perl -w"?
Example is the Net::Dev::Tools::Syslog' that produces messages like

t/01Modules....Variable "$_sock" will not stay shared at
/usr/local/share/perl/5.8.8/Net/Dev/Tools/Syslog.pm line 1757.
Variable "$_fwd_sock" will not stay shared at
/usr/local/share/perl/5.8.8/Net/Dev/Tools/Syslog.pm line 1758.

These are particularly annoying when using Test::... modules.

I tried something like

{ local $^W = 0; use Net::Dev::Tools::Syslog; $^W = 1;}

but that does not seem to produce the goodies: the messages
keep popping up.

Any suggestions on how to suppress these messages, notably when
using in the context of automated testing vua the Test::... methods?

TIA