To install an x86 additional driver on a Windows Server x64 host, you first need a running Win 7 x86 system.
Install the printer by choosing the correct driver.
On this x86 system, locate the directory \Windows\System32\DriverStore\FileRepository\ntprint.inf_xxxxx, then copy all files and sub-directories from ntprint.inf_xxxxx into same location on the Print Server . If the x64 host asks for the NTPRINT.INF on the Windows Media during the installation of the additional driver, simply browse to this location and complete installation.