If the OP puts the answer in the body of the question, or if the answer ends up in the comments on the question, leave a comment asking the OP or the commenter to put the information in an actual answer.
If that doesn't happen within a couple of days, feel free to put the information in an answer yourself. To prevent the appearance of reputation point whoring/stealing, it'd be best to mark the answer as Community Wiki. This way, at least, people can vote on the answer and future readers can find the better solution.
See also: