Ran into the same problem

Some console commands are most useful if their output can be used as an argument value in other commands. In console, this is done by "returning" value from commands. Return value is not displayed on the screen. When you type such a command between square brackets '[' ']', this command is...

there is no way to set it in export as that gets tailored for terminal you are using. On the other hand you can try to use login options that set some auto-detected values for the terminal session. http://wiki.mikrotik.com/wiki/Manual:Console_login_process#Console_login_options set width reasonably...