First hint to get a full working PGP 8 version (instead of a crippled Freeware Version),
without having the appropriate serial number:
Get the pgpclientlib.dll and the pgpkeys.exe from the Beta2 version.
Patch the pgpkeys.exe with the PGP8b2 timebomb remove tool (available at ftp.zedz.com/pub/crypto/incoming).
Change in pgpclientlib.dll the following string "PGPclDisplayTimeoutMessage@12" to "PGPclDisplayTimeoutMessage@16".
Install the Freeware version, do NOT reboot after installation.
Replace the pgpclientlib.dll in %WINDIR%\System32 folder.
Replace the original pgpkeys.exe with the above patched pgpkeys.exe (from the beta2).
Reboot.
After doing so, PGP 8 Build 405 is working - but the integration into Outlook Express is missing, because the
module (pgpoe.dll) was not integrated at installation time. May be someone have to figure out how the plugin is integrated...

I am working at an other solution, and, i am sure it will work. Be patient, I will publish it also HERE.

Peter