Inserting session cookies into Mozilla sqlite

I want to insert cookies captured from wireshark into sqlite's firefox to try and "sniff session", but I've run into some problems. I tried various sites and from what I've seen the cookies with actual session ID are NOT stored in sqlite, so I can't insert them there. For example on stackoverflow there is a cookie acct=t which is not saved in the db. Does anyone know how can I circumvent that?