Serial Named Pipe Unrecognized Windows 7

I created a named pipe serial hardware and supplied '/tmp/debug' which I created using mkfifo

This is the snippet from ps -aux
-chardev pipe,id=charserial0,path=/tmp/debug -device isa-serial,chardev=charserial0,id=serial0

failure@ubuntu1:~$ ls -al /tmp/debug*
prwxrwxrwx 1 jgp jgp 0 2012-03-03 18:40 /tmp/debug
prwxrwxrwx 1 jgp jgp 0 2012-03-03 18:40 /tmp/debug.in

However inside the Windows 7 guest (even after a restart) nothing is recognized. Even after going through the add legacy hardware motions it's still not picked up.