As I stated above: https://bitcointalk.org/index.php?topic=57175.msg680818#msg680818
the first and repeated question you are going to get is "how do we know you are not selecting your buddy's ticket to be the winner".
Even if you release the code that selects the winner, or even if you released all of your code, this does not prove you are randomly selecting the winner.
It looks like you may be kind of new around here so you many not know that due to the irrevocable nature and relative anonymity of Bitcoin transfers many members of the Bitcoin community have been personally ripped off or seen others be ripped off in many different and creative ways. This means that the customer base you are dealing with, your customer base, is a lot more skeptical and paranoid than the general public. You really need to know and understand this and take it into consideration in any new Bitcoin venture. Your points that people generally trust and believe certain things in the general population, while possibly true, have no purchase within the Bitcoin community.
Your competitors have found ways to get around this by having an external publicly available and publicly verifiable way to select the winner. You are and will continue to be at a huge disadvantage to your competitors until you solve this issue.