Two-way Authentication Load Balancing - Forward Client cert to node

I have been requested to setup VIP with Two-way Authentication Load Balancing and Forward Client cert to node. Two-WAY authentication between Client and F5 seems quit straight forward to achieve ; but here the requirement is that F5 should perform as normal SSL VIP ( perform all SSL offloading) and the client cert presented needs to be forwarded to backed IIS web-served which will do all validation of certificates. Not sure how to move forward with this .. Is there any iRule which can help in this... Please suggest .. pretty new to iRules though...