Replace #channel with your channel name.
Code:
#autovoice on
on @*:join:#channel: {
  mode $chan +v $nick
}
#autovoice end

on av:text:!av &:#channel: {
  if ($2 == on) { .enable #autovoice }
  elseif ($2 == off) { .disable #autovoice }
  else .notice $nick Incorrect format.  Use !av on or !av off.
}

Use:
!av on
!av off

Then, you can put the people you want to have access to enable/disable that into your users list so it looks like this...

av:nick!ident@host.com
av:nick2!ident2@host2.com
etc.

You can use * in place of nick or ident or host if you want to.