i don't know flash but i do know a fair amount about slop detection, so i made this pic and explanation. i am not sure that it is all right as i have never tried programing something like this (other then on paper). also the math at the end may not be right as i haven't don't stuff like that in about a year.

first make two points (point 1 and 2) keep them the same distance all the time.
then make each one have it's own gravity pulling it down. this should get you
a stick that falls down, so you also need to make each one not fall though the ground.
now you chould have a stick that acts like a really stick.
next we are going to find A and B. the way to do this is to subtract one of the y values
from the other y value (do the same with the x values). now divied B by A (so B/A)
and you will get a decimal. lets call it D
now that decimal will need to be converted in to a degree
(we are going to call the degree R) before we can use it.
so lets do that, set up something that looks like this
D/1 = R/90
now R will be a number between 0 and 90. just rotate yoour player by R degrees and you
should be good. oh and make sure to place his feet at the mid point of line C.