How to change the username Mac OS sends to print server

[Javier Rodriguez]

I have the following problem: I want to send print jobs to a network printer/ print server with a different user name than the one I have on my IMac. This works fine with "lpr -U username", but if I want to print from any Mac OS application via the print dialog I couldn't do it. I already tried to edit the printers.conf, changing the DeviceURI to ipp://username:password@printserver:631/queue , which didn't work. If I add the line "AuthInfoRequired username,password" to printers.conf an authentification window opens up when printing, where i put the username and password for the print server, but it seems Mac OS still sends my IMac username to the print server. Does anyone have an idea how to fix this ?