The method I use is to stay away from the station until you are lined up with the entrance, and then just head directly inside at full speed with power set to engines, as soon as you hear the 'scan detected' just hit boost, once you're inside they cannot finish the scan unless they still somehow have line of sight on you. I dont even bother with silent running anymore. I get the feeling the system needs tweaking as it just feels too easy to get inside with illegal or stolen goods.
If you want to practice it with no danger then just go in and out of a station with no goods in your cargo at all, if they manage to finish the scan (something along the lines of, 'ok we're done here, move along') then you failed. You might even be able to practice this in the tutorial that starts you off in the station, the travel tutorial i think, but i dont even know for sure if there are security ships in that mission and if there are I dont even know if they scan.
good luck!