VS HTTPS and Pool HTTP

You just need to create the pool members as http inside a https VS and make sure you have the VS doing SSL offloading.

If I may add, the port translation option in the virtual server's configuration is what allows this to work. This is set by default on a standard virtual server. As Lapayne says, create a pool of port 80 servers and apply a client SSL profile to the virtual to offload SSL.

Here is a good guide on configuring VS's, it's version 10 but the principles are the same.

http://support.f5.com/kb/en-us/products/big-ip_ltm/manuals/product/ltm_configuration_guide_10_0_0/ltm_virtual.html