Best Practice for Changing the Cell-Renderer in a TreeTab

I've implemented a TreeTable (sap.ui.table.TreeTable). Now, I would like to change the way how table cells are being rendered. Intuitively, I would create a subclass "myrenderer" which extends sap.ui.table.TableRenderer.renderTableCell and assign this renderer as cell renderer with something like (pseudocode):

myTreeTable.setCellRenderer(myrenderer);

Any help/hint would be appreciated. An example would be appreciated even more ;-).

Bye

    Christian