ActionScript 2.0 :: Local Shared Object Or Cookie To Track Time

I need to make a local shared object (or javascript cookie function- below) that I can use to calculate the time since an ad was last loaded. It's an expanding ad, and I only want it to expand once every 2 hours. (Trying to keep the expanding-annoyance to a minimum!) I understand the basics of creating an "lso" but the action script for retrieving the time, placing it as a variable in the lso, and later retrieving it to figure the time is well beyond me. I considered a normal browser cookie, set to delete after the session, bypassing all time calculations... Forcing javascript to create a cookie ONLY when flash tells it to (after the ad has expanded) is tripping me up and creating a function to check for the cookie on the first frame to decide whether or not to continue is also beyond my simple animation skills.