Remapping the AltGr key to Control

[quidH4]

Is there a way to remap the AltGr key to Ctrl with setxkbmap?
I've already checked the option section in
"/usr/share/X11/xkb/rules/base.lst" but I didn't find an entry for
AltGr...

I also tried xmodmap, however some xmodmap entries on my /.xsesssionrc
seem to be ignored at system startup,
and they don't take effect. Therefore I decided to achieve that
through setxkbmap or xkb...

My OS is  Debian Wheezy and the keyboard layout is set to gb (on an
Italian keyboard).


That's what xmodmap prints:

shift       Shift_L (0x32),  Shift_R (0x3e)
lock        Caps_Lock (0x42)
control     Control_L (0x25),  Control_R (0x69)
mod1        Alt_L (0x40),  Meta_L (0xcd)
mod2        Num_Lock (0x4d)
mod3
mod4        Super_L (0x85),  Super_R (0x86),  Super_L (0xce),  Hyper_L (0xcf)
mod5        ISO_Level3_Shift (0x5c),  Mode_switch (0xcb)


And that's waht xev prints when I press AltGr:
...
state 0x90, keycode 108 (keysym 0xfe03, ISO_Level3_Shift), same_screen YES,
    XKeysymToKeycode returns keycode: 92
...

Thanks for help.