With the diagram wizard you can only generate upto 32 different y-axes. To get more different axes, you have to add manually the supplementary axes and assign the curves to them. Then save this diagram as template (right click on diagram in object list -> Save as template..). In the “Template wizard” (Step 1), don´t forget to uncheck the “Save as dynamic template” option.
Once this is done, you can select the desired functions and create a new diagram with the diagram wizard (Go to Template Tab).