hmmm ... I just realized this can be made much simpler. You said that you can perfrom the following tasks
- connect to the server normally
- attach tmux
- run irssi/other-things with no unicode bugs.
If you can connect to the shell of your server, why not add
tmux attach to your .*rc file? If you would like to attach to tmux most times you connect to the server, just have the server automatically attach when you connect (every time).
Using some putty-specific connection method is a bad idea, in my opinion, because it may not work well when/if you change your method of connecting ie. if you change to a non-windows computer. So, instead of attaching to the session by using putty's "remote command", just connect regularly. If you are using a bash shell, add this to the
$HOME/.bashrc file on the server:
if [[ ! -n $TMUX ]] ; then tmux attach ; fi
Then, as soon as you connect it will automatically attach to the tmux session. You can always leave tmux by using detaching:
tmux detach (or you can kill every tmux session
killall tmux if you want to start over).
Of course, if you like, you can then begin to think of a more complex tmux attachment script that creates a custom-new-session OR attaches. Personally, every time I open a terminal, it launches a tmux session script (113 lines long), which sets it up just like I like it ... or it attaches if the session already exists.