The previously developed technique for calculation of ionization probabilities in low-energy heavy-ion collisions [A.I. Bondarev et al., Phys. Scr. T156, 014054 (2013)] is extended to evaluation of positron creation probabilities. The differential probabilities are evaluated by two alternative methods. The first one uses hydrogenic continuum wave functions, while the second one uses discretized continuum wave functions corresponding to a finite basis expansion. These methods are applied to the calculation of the differential positron creation probabilities in the U91 +(1s)-U92+ collision. The results obtained by both methods are found in good agreement.