I am using you Events Booking Component for a series of events around the country... we need the option for registrants to preorder tshirts and hats... I'm in the process of creating custom fields, but am a novice joomla user. In this case, I'm creating a radio list for users to select the tshirt size. Where I get stuck is what I am supposed to put into the Values, Default Values, Fee Values and Fee Formua fields. Any suggestions?