That's no problem. The probelm is:
/echo 3 Hello!
won't save the line color 3 to the file.
I want't it to save the line color like this:
/echo <Ctrl+K>3 Hello!
When it's mirc's own message (like connection timed out, invalid parameters and so on)
That's because I want to display the log file before I join the channel, so I have a preview where I last was. And the colors would be a lot of better than gray text
Logging started
*** Joined #mirc
*** The topic is ''
*** You have left IRC
Logging stopped

(an examle, not an actual logfile)