We investigate under which circumstances one can show the existence of leptonic CP violation with the help of a positive or negative signal in neutrinoless double beta decay. The possibilities of cancellations are investigated for special mass hierarchies and the different solar solutions. The possibility that the mixing angle connected with the solar neutrino problem is smaller or larger than pi/4 is taken into account. The non-maximality of that angle in case of the LMA solution allows to make several useful statements. The four different CP conserving possibilities are analyzed. It is implemented how precisely the oscillation parameters will be known after current and future experiments have taken data. The area in parameter space, in which CP violation has to take place, is largest for the LOW solution and in general larger for the inverse mass scheme.