So there are two things that should be the end result:
* mIRC should keep not-repeating-line separators
* mIRC should however allow you to echo a character that is also the line separator, and have it not treated as a line separator
This being said, I don't think mIRC tracks when it last said a line-sep so this could get ugly..
But I guess it only needs to remember if the last line of a given target was a line-sep.