Accessing the ItemRenderer in a Flex spark DataGrid

I did not found a way to do this with the spark DataGrid, only with the mx one, the developers encapsulated very well the renderers. Because Flex is open source I read the code and finaly found a way to access the renderers. I could not use bindings in my case and I did not had other idea at that moment and because the renderers are very optimized it is hard to make them refresh.