ssh with unstable and mobile clients

Revisiting two old ssh points:-

1. Smart Tricks with ssh mentioned ServerAliveInterval 3600 and the page I referenced for it mentions ClientAliveInterval on the server-side. Is there any reason not to use that?
2. ssh security mentioned sslh to put ssh on port 443, but it seems Top J2ME MIDP Application MidpSSH can’t connect to ssh on other ports. The instructions in the manual about port numbers don’t work for me if I put in 443. I get java.lang.SecurityException. Anyone know why?