so in the ACE config the "layer4-payload offset 43 length 32 begin-pattern "(\x20|\x00\xST|([^\x20 ^\x00]\xST))"" should generally correlate to BIGIP SSL persistence. SSL persistence is usually used for non-terminated SSL sessions, and tracks user connections using the SSL session ID. At least that has been my experience converting 50+ ACE's to LTM. That said SSL persistence is NOT always reliable as I do believe that IE specifically re-negotiates every 2 minutes, so that session ID value can change whenever client re-negotiation takes place. if you use SSL persistence you should also use source ip as a backup persistence.