Wanidoob,
what I meant is that you don't have to fiddle with the port number avast listens on. Just choose one port and let it there. Having the listening port in avast set to 110 makes things easier if you want your mail client to download mail directly through avast, since 110 is usually the default number and so you need not to change it. There is no need to force avast listen on two ports for whatever reason - as you are suggesting in your original post.
The configuration suggested by Technical seems pretty reasonable to me. It should work with SSL tunnel. I don't know how SSL tunnel works in detail, so I cannot help you with it's configuration right now.
In general you can firstly setup the SSL tunnel and your mail client to work together - and forget about avast for a moment. You will end up with something like Technical offered. That is, you'll have a service running on your localhost, eg. on port 11110, which connects to the gmail pop server via SSL. That is, instead of pop.gmail.com, port 995, you would be connecting to localhost, port 11110, and the connection to gmail will be realized by the SSL tunnel. In order to work, you would have to setup the localhost server in your mail client. Technical's config is further complicated by the presence of SpamFilter, but let's omit this for a moment.
In you mail client you now have localhost as a server and 11110 as a port. If this would work (with SSL tunnel setup correctly) all is fine. Now it's time to add avast scanning to the whole stream. Best place for avast is between your mail client and SSL Tunnel. Avast automatically monitors all connections to port 110, eg. pop.myisp.com:110, but in your case there is no connection to port 110, instead 11110 is being used. So firstly you'll have to add PopRedirectPort=110,11110. Now avast will redirect (monitor) both 110 and 11110 ports. Your connections are directed to localhost:11110, but under standard setup localhost is ignored and not monitored. So secondly you need to add IgnoreLocalhost=0.
Finally, if you have problems starting the SSL Tunnel service, please use Control Panel / Administrative Tools / Services, there you can change the status from stopped to started.
Lukas.