virtual server config

Well, this is up to you. 
Per my experience, some customers prefer to offload the SSL decryption task to the F5 unit, so that they don't have to perform additional decriptyon on the backend server farm, saving resources. This is usually also allows more agile administration, because you'll only need to renew the certificates on one appliance (BIG-IP) instead of every server. 
Other customers prefer to perform SSL encryption in the backend as well because they prioritize information security across the whole network. 

You might want to discuss this with your engineering team, and if your servers require the SSL handshake to be performed, you'll need a serverSSL profile.