I attempted to do it using the low level method and sending notes to three different channels without success but I'm no MIDI expert.

use Win32::MIDI;
my $midi_obj = Win32::MIDI->new();
$midi_obj->openDevice(0);
## Low-Level Method -- Writing Directly To The Device,
## Creating Your Own MIDI Messages
my @on = ("\x00\127\127\x90","\x00\127\160\x91","\x00\127\090\x92");  
+  
my @off  = ("\x00\127\127\x80","\x00\127\160\x81","\x00\127\090\x82");
for (@on) { $midi_obj->writeMIDI(unpack("N",$_)); }
sleep(3);
for (@ff) { $midi_obj->writeMIDI(unpack("N",$_)); }
[download]

Perhaps you should contact the author and see if he can help.