problems with banana roll i cannot keep the cake from breaking when rolling

What I do is this: 1) Make sure you bake the cake in a buttered jelly-roll pan lined with parchment. Do not overbake or cake will be dry. While cake is baking, prepare a thin tea towel before removing cake from oven. Lay it flat on the counter. For a chocolate cake I sift cocoa powder over it; for a vanilla cake powdered sugar. Take cake from oven and invert over the tea towel. Peel off the parchment and trim a very thin strip off each of the four edges with a sharp knife (you don't want the crispy parts interfering). Overlap a short edge of towel over a short edge of cake and Immediately roll cake in the towel and allow to cool completely on a wire rack, still rolled in its towel. When ready to frost, unroll cake gently, keeping it on the towel, and spread filling. Using the towel as a support, re-roll around the filling. Being sure not to overbake, trimming the edges so they are not dry or crispy, and allowing to cool in the rolled position to "stretch" the crumb, should all help.