Quote from the manual:
http://www.amibroker.com/guide/afl/enablerotationaltrading.html
The score (PositionScore) for all securities is calculated first. Then all scores are sorted according to absolute value of PositionScore. [...]The score has the following meaning:higher positive score means better candidate for entering long tradelower negative score means better candidate for entering short trade
The score (PositionScore) for all securities is calculated first. Then all scores are sorted according to absolute value of PositionScore. [...]The score has the following meaning:
So just make the PositionScore LESS than zero. That is all you need to do.