Hi,
Currently there is not any option to define the asset's paths. It must be done modifying the registry keys, as described in the post.
Anyway, it's much more simple that it seems. It can be done in this way:
1) Install the assets locally in any workstation, using the default procedure (Update Manager).
2) Copy assets from C:\Users\<user name>\AppData\Local\Itoo Software\Forest Pack Pro to the desired location.
3) Use registry tool to modify the location: HKEY_CURRENT_USER\SOFTWARE\Itoo Software\Forest Pack Pro\LibraryDir\Forest Library, or alternatively using the Forest Library Browser->Preferences->Library Paths.
4) If needed, add the texture paths to 3DS Max->Customize->Configure User Paths->External files.
We'll see if this procedure can be improved for next updates.