(as I have included in my last mail...)

  T.10.1 - The Damage Prevention Step can be charted out like this: [Fifth
Edition, Page 50]

 1. Beginning of
  Damage Prevention - Play all abilities which either trigger on damage
being "assigned", or which automatically
  prevent damage. Play these as a Series (see Rule T.9).

 2. Main Part of
Damage Prevention - Play any number of
  Batches (see Rule T.8) of spells and abilities which either prevent or
redirect damage.

 3. End of Damage
  Prevention - Play all abilities which automatically redirect damage or
which say they are played at the end of
  damage prevention. Play these as a Series (see Rule T.9)

4. Damage is Successfully Dealt - Play all abilities which
  trigger on damage being "dealt". Play these as a Series (see Rule T.9).

5. Remove Dead Creatures a. Play any
  Regeneration (see Rule G.32) spells and abilities on creatures with
lethal damage. Play these in a Series (see Rule
----------------------------------------------------------
****** b. Destroy any creature with lethal damage *******
----------------------------------------------------------

The original damage is done simultaneously and then after this is handled
then the redirection will cause a new damage prevention phase, as well as
damage resolution.  After the first damage is processed and the maniac is
killed the rest of the damage that was redirected will be lost because the
target is dead and gone. (damage prevention step 5).  This is a rule as
well.  I will include it at the end of this mail.

As far as beginning a new damage prevention phase, this MUST happen.  If
it does not happen then the damage will not be doubled.  The step one of
the damage prevention says to apply effects that trigger on damage being
assigned.  If you do not begin a new damage prevention the damage will not
be doubled.  See this ruling:

T.10.6 - Damage redirected during step 3 is not considered successfully
"dealt" during this damage prevention step.
  See Rule T.10.11. [Fifth Edition, Page 51]

This is the rule about an invalid target for damage redirection:

T.10.7 - If the permanent is no longer a creature at the start of damage
prevention, the damage is never assigned and
  is just ignored. [Aahz 11/08/96]
 

This will apply to a dead creature as well.  There is a ruling about
damage and invalid targets.  Dan will tell you about his as well.  A blood
pit blocking a force of nature.  If you sac the blood pit after
declaration of blockers you will take no damage.  The damage is applied to
a creature that is not there, and therefore it is lost.  (kinda silly I
think but that is the way it works.)