Despite the lack of support from Apple for Boot Camp 5.x on a 2009 MacBook Pro with OS X 10.8.4, I got the Windows 8.1 Preview installed.
Via Boot Camp 5, download latest Windows support software and proceeded with install of Windows 7
Inserted Windows 7 DVD when Boot Camp requested it to avoid warning/error message with Windows 8 DVD (“Windows 8 is not supported on this Mac”)
Upon restart, replaced Windows 7 DVD with Windows 8.1 Preview DVD
Windows 8.1 Preview install began
Formatted BOOTCAMP partition to install
Proceeded with installation as normal. After installation, confirmed several device drivers did not install
Proceeded to install Boot Camp 4 drivers in compatibility mode to complete driver installation and restarted
Everything works well and as expected. I did download and attempt to install the Boot Camp 5.0.5033 drivers (DL1638) however there is a definite hardware limitation/compatibility issue that prevents the install.
No matter. I am sure there are certain features that do not function properly but for what I need it for … it works like a CHAMP!!!