I don't have Outlook set up to test this but a couple of ideas to try

use strict;
use warnings;
use Win32::OLE 'in';
use Win32::OLE::Const 'Microsoft Outlook';
use Mail::Outlook;

my %hash = (
     To      => 'user@mail.com',
     Subject => 'Blah Blah Blah',
     Body    => 'Yadda Yadda Yadda',
  );
my $outlook = new Mail::Outlook();
my $folder  = $outlook->folder('Drafts');
my $message = $outlook->create(%hash);

my $doc = $message->{'message'};

# type olText=1 
my $uprops   = $doc->UserProperties;
my $newprop1 = $uprops->Add('X-ICCategory',1);
$newprop1->{'value'} = 2;

for my $prop (in $uprops){
  printf "%s %s\n",$prop->{'name'},$prop->value;
}

my $PropName = 'http://schemas.microsoft.com/mapi/string/'
             .'{00020386-0000-0000-C000-000000000046}/'
             .'X-ICCategory';
            
my $pa = $doc->PropertyAccessor;
$pa->SetProperties($PropName, 2 );

[download]
poj

In reply to Re: Adding custom header to Mail::Outlook::Message by poj
in thread Adding custom header to Mail::Outlook::Message by maskull

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