A variation.

#! perl -sw
use strict;

my %comments = (
    FED00123 => 'Comment FED00123',
    FED00124 => 'Comment FED00124',
);

$/ = 'UNIX'; ## Read the bulk as a block

while( <DATA> ) {
    my( $id ) = m[(FED.....)];
    print;
    { local $/ = "\n"; print scalar <DATA>; } ## tidy up
    print "\n$comments{ $id }\n";
}

__DATA__
...
[download]

Gives:

C:\test>junk48
=====EDO=FED00123=====
XXXXX
XXXXX
XXXXX
XXXXX
XXXXX
UNIX Page: XX

Comment FED00123
=====EDO=FED00124=====
XXXXX
XXXXX
XXXXX
XXXXX
XXXXX
XXXXX
UNIX Page: XX

Comment FED00124
[download]