There is a list of groups that SBS will show the folder in RWA only if one of them are set to have full access. This list can be seen by going to the SBS console, going to the file share tab, and double clicking on the share to edit permissions. On the right side will be applied groups that have access, the left side shows an available list of groups. These groups are SBS specific, and these are what SBS looks for to see whther or not to list the Share on RWA. Remove them, replace them with Domain users, single users, etc – whatever, and it will hide the share in RWA.