One last word of advice, but not particular to passing the CASA interview. However, it is certainly a question I asked more than once in a former life and I believe is one that CASA should always examine in some depth.
Before you accepted the gig, did you get information on how well your company is funded, whether it is profitable in its own right (as opposed to some tax write-off) and the bossman's attitude to spending a buck on training and support services? Will you have any budgetary control? Even if he is the nicest guy on the planet, if he is stripping it of profits, or making a loss, or if you have to grovel and beg to get minor support services in order to meet compliance, then you really do need to think about how badly you want the job.