If it is an obscure system, feature, or area of knowledge, and someone will have to invest significant time to understand the issues involved, then you may need to put in a significant bounty - few people may be interested, and they may not want to spend time on the issue - this is a answerer's market, and you may need to put up some real reputation if you don't see any answers after a bit. If the question is getting comments, but no answers, check that you are asking a good question and are sufficiently clear.