A topic from AEG's L5R CCG Rules forum, copied for Oracle of the Void from the Wayback Machine (its copy), so posts it didn't save are missing. Players' names are left out; the rules officials are named. Rulings are as they stood on these dates; later rulings, the rulebooks and the Rules Archive may differ.
There have been a lot of questions relating to redirection. Almost every single one asked can be answered by reading the Diamond rulebook, pg. 74. In short, that says:
1. You can't redirect costs.
2. You can only redirect effects to something that could have picked in the first place.