How to switch an index image from a wim to another wim ?

Hello,

I created an updated windws 7 sp1 with update iso.

I don't knwo why but it appeat that my index:6 of my install.wim is corrupt.

I would like to extract the index:6 of a "clean" install.wim and replace to my corrupted index:6 wim.

I try to di this wih dism :

Mounted the good index:6

Renamed the mounted folder.

Unmounted with discard

Mounted the "bad" index:6

Renamed the mounted folder

Renamed the "good" folder index:6

Unmountend with commit ( in order to save the good index:6 in the install.wim which had the corrupted index:6).

Dism don't want to do this !

I tried with WinToolkit, using the wim manager, and i have exception.

Is there a proper way to do this ?

Anyone could help me please ?

Thanks a lot

Best regards,

Nixeus