Sorry brother, this is against the guidelines and has been answered in other threads and posts before. Basically, it is illegal unless you have arranged it with your doctor and it has been approved under the Special Access Scheme.
As for importing them illegally, sometimes they get through and sometimes they don't. It depends on quantity, packaging and even the individual officer's discretion. Odds are you might get a love letter from Customs or have them discuss the issue with you in person depending on how large an amount you try to import.