Remote desktop : unable to print on network printer

Hi to all,
After looking around, I still can't print from a remote desktop
connection on our "local" network printer.

I've tried the procedure with detailing a local redirection of the LPT
port to a network port,
I've enabled the RDC printer redirection
I've checked that drivers are installed on the other end

But, nix. I'm afraid I'm doing something wrong during the frist step :
I often get a "port already in use" message.
Any hint ?

Thanks in advance !

Damien