Question about CUPS settings

Hi. I am new here and firstly I'd like to appreciate this space.

My environment has a lot of linux versions, like: RHEL 5.4/5.8/6.2/6.3 - Centos 5.4/5.8 - Fedora 16, etc

Using the RHEL 6.2/6.3 and Centos 6.2, for example, I can send the document to the printer and I am asked about username and password, because I have setting the option AuthInfoRequired username,password (and this is what I want).

So, if I use the older RHEL/CentOS versions, using the same setup, this not happen. No pop-up is showed.
If in the DeviceURI I put the address + user and password, It works, so the connection is ok, but if I set "AuthInfoRequired username,password" and I not asked to write username and password.

Someone have some suggestion?

Note: In the RHEL 6.2/6.3 the CUPS version is 1.4.2. The older Linux version use CUPS 1.3.7.

Tks a lot,
Tiago