Automate an interactive command which use /dev/tty

Question

well pretty much it's in the title.

I've a interactive command. This one ask for a password through /dev/tty. I use this command within a shell script. So the command should read the information through stdin. I've explored some ways to do this:

• Seek for an option to force stdin (à la ssh with the -T option)
• The easy ones, stream redirections
• The coprocesses (|&) to setup a communication between the current script and the coprocessed command
• I've tried named pipes

I'm running this script in a Korn shell (AIX). I can't use external tools such as expect or empty neither.

Do you have any clues ?