log of a product(...) to be sum(...) of a log

Hi people
Ive spent about 6 hours reading thru the ref manual and an hour
googling but the closest Ive got to trying to simplify a (ratio of a)
product of (independent) normal distributed (variance==1) random
variables i.e.

p(x,m) := (2*%pi)^(-1/2) * exp((-1/2)*(x-m)^2)

log(  product( p(x[k],m[1]), k,1,n ) )  ) -  log(   product(
p(x[k],m[0]),k,1,n ) )   );

(call this equation (A) )

is the following

(%i16) defrule(rule1, log(product(z,k,1,n)), sum(log(z),k,1,n) );

(%o16)       rule1 : log(product(z, k, 1, n)) -> sum(log(z), k, 1, n)
(%i17) disprule(all);

(%t17)       rule1 : log(product(z, k, 1, n)) -> sum(log(z), k, 1, n)

(%o17)                              [%t17]
(%i18) rule1 (log(product(z,k,1,n)));

(%o18)                               false

Ive tried declaring log and/or product to be a noun, Ive tried quoting
them too. I know this "Equation A" simplifies to something simple in
terms of m[0] and m[1] and sum(x[k]) but just cant get maxima to
consider log of a product to be sum of a log (i.e. cant create a
working "rule1")

Please help?