well it s a bit embarrassing:
lognormal distribution cdf can easily be calculated if you know how to calculate the cdf of standard normal distribution.
anyway.. as nobody for the last day posted a reply, i think the following equation will be useful for some;
lognormal(x,mean,stdev)= standardnormal( (ln(x)-mean)/stdev))
assuming lognormal(), and standardnomral() are cdf s.