I have installed MOS3.1+PU 3.1 (default e-uae version 0.8.29-WIP4). What I want to achieve is to create a basic 3.1 enviroment and install WHDLoad on it but I can't figure out how t work with the GUI frontends! What exactly do I have to select in order to operate SYS:Emulators/E-UAE-HardDisks/Workbench as a valid HD on the emulated enviroment? I have set its path via UAE Launcher but the HDToolBox (on the Install 3.1 disk) does not recognize any HD whatsoever...

Wow!
If you get that one working, let us know how its done.

Hey, well.. I don't know whether you are jocking or not but on WinUAE is fairly simple to do it :P But hadn't any luck with E-UAE so far :(

If you prefer winuae, then install the system under winuae, and when you finished, take the hardfile, or the directory (if you don't make hardfile)and put it in your MOS system.
Editing the config file for uae is simple. There are some samples in conf directory. The trick is te following, if you using directory, thet fisrt you set the device (for example dh0:, and after you set the long path which is in your system. so not just the directory in your progdir. for example: dh2:emulators/euae/harddisks/system/