Proxy SSL configured as per manual, connection reset occours

Interesting, so it looks like there's an alert after the initial handshake fails. You can't really do pool switching in an iRule like that either. ProxySSL allows a client and server to negotiate an SSL session directly, so at the end of a handshake, client and server A have a shared symmetric key. If you then divert traffic to another pool, the client doesn't know that and therefore can't communicate with that new server with its established session.