If you are on 1mg or so of suboxone a day, you would need A LOT of codeine to break through the sub. At least that was how it was for me - I only tried twice to break through the sub (at 1mg a day) and both times were completely unsuccesful.
If the sub isn't doing the trick, stop taking the sub and switch to codeine only. Codeine is a lot easier to kick than suboxone - and I say this with experience. I lived in Paris for a year, where they sell Neocodion pills (15mg of codeine and nothing else) and by the end of the year I was taking 1,300mg of codeine daily. When I quit, the withdrawals only lasted three days and weren't that terrible as long as I took my xanax. I even went to school and functioned normally during the withdrawal. Suboxone withdrawals, on the other hand, were far more intense than codeine withdrawals and also lasted two weeks +