HP 4350N, Windows 7, Manual Duplex not available

[KGroninga1]

I have a LaserJet 4350N (without the Duplex attachment).  My OS is Windows 7 64-bit and I have the most up to date version of the PCL6 driver installed.   According to the documentation, I should be able to set the configuration to tell it that the automated duplex attachment is NOT installed, but there should be another option for 'manual duplex' = 'enabled'.   No where in the configuration dialog is there an option for 'Manual Duplex' = enabled.

 I also have two Win2K machines which I also installed the latest PCL6 drivers and in those configuations, I can set the Duplex Attachments to 'inactive' and still have the Manual Duplex enabled and actually get it to work.   Once I send the printed output, it will print 1/2 of the job, then ask me to load that back into Tray 1 so that it can print the back sides of each page.

 Why in the heck am I not seeing that Option for 'Manual Duplex' in any of the pages of the 'printer properties' on my Win 7 machine?  Is it the OS?  Is it the driver?

I've even tried changing the driver to the PS version and the PCL5 version.  In all cases, I'm seeing nothinjg on that dialog screen for 'manual duplex' enabled.