Hi,
sorry but I haven't followed your suggest.. I hated the x86 folder, in particular I hated that this was an "Imposition" and not a free choice of the user... so I've done this:
- ) Regedit -> changed the default path "CommonFilesDir (X86)" and "ProgramFilesDir (x86)" making equals to 64bit version;
- ) modifing all the references to x86 folders in registry in 64bit references;
- ) copy and NOT substitute all the progsx86 folder in the progs folder.

Now I'm free to decide in what place of my progs dir the program will be installed (for default it's in progs dir, and I think i'll install all in it, using the appropriate suffix, in case of necessity, to indicate the architecture). With this change I've got also the benefit that all the defaults programs are in 64bit version (IE, WMP...).
I've got no problem for "hardly search of plugin" because IE and WMP are not my prefered sw.. (for example firefox and vlc are much better).

I hope my hours for modifing vista are useful to somebody else...

There's still just another 2 problems:
- ) It's possible to "unlock" totally the register? (There are some keys that I can't change because of some limitations-file in use-some other reasons... like some keys refered to IE);
- ) it's possible to "totally unlock" the progsx86 folder to delete it permanently (now in my pc is still there..), i.e. some software like "xp-lite" that disable the control on system files deletion ecc... that permit me to del this folder?


Thanks

(PS: If there's someone that want to do the same as me, I suggest to do a backup of all the registry and, at the end ow work, to run some programs to optimize, clean and defrag registry)