I have quite a bit of personal distaste for Config::General but it might be what the doctor ordered in this case. You may have to adjust and I'm not sure if there's a setting to retain =s on the serialized config.

use Config::General;

my $config = Config::General->new(-String => [ <DATA> ]);
my %data = $config->getall();

$data{be_address} = "192.168.106.55";

my $new_config = Config::General->new(\%data);

print "Original:\n", $config->save_string();

print "\nNew:\n", $new_config->save_string();

__DATA__
be_address = remote-be-address
be_port = 9000
svs_port = 8733
log = log.txt
verbose = 10
screen_print = true
fe_id = 1
encryption_key = default_encrypt
fe_id_last = 1
mtu = 45K
cpu_throt = 100
bandwidth_throt = 100
system_tray_icon_enable = true
email_notification_level = 10
web_access_enable = true
sync_enable = true
software_settings_interval = true
min_space_for_dist = 30M
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