Roughing and Re-roughing problem

When using 'Roughing' with a mill window in Creo 5 I've been putting a value of 2 or 3 into the parameter CORNER_ROUND_RADIUS as it stops the cutter squawking when it goes into internal corners. However, when I then use Re-rough with a smaller cutter the software doesn't recognise the extra material left in as a result of the CORNER_ROUND_RADIUS parameter being greater than zero, which can cause the second cutter to bite off more than it can chew. Anyone have any idea how to get Re-rough to recognise the additional material and create an appropriate tool path?