Hi Rafael,
If you want to passthrough the HTTPS just configure a VIP without a client or server SSL profile. You could probably use a Performance Layer4 VIP with a FastL4 profile. Optionally, if you want to send an HTTP response back to the client if the pool is down, you could add a client SSL profile and use an iRule like this:
HTTPS passthrough with a Fallback URL
http://devcentral.f5.com/wiki/default.aspx/iRules/HTTPS_passthrough_fallback_URL.html
If you want to decrypt the client side SSL but re-encrypt the server side connection, you can add both a client and server SSL profile to the virtual server. This allows you to inspect and modify the HTTP but still keep all communication over the wire encrypted.
Aaron