1. An external control device for use with a neurostimulator coupled to a plurality of electrodes capable of conveying electrical stimulation energy into tissue in which the electrodes are implanted, comprising: output circuitry configured for communicating with the neurostimulator; a user interface including a display device and at least a first control element configured to be actuated to selectively place the external control device between a first mode and a second mode, and at least a second control element configured to be actuated to define a plurality of different candidate electrode combinations; and a processor, when the external control device is in the first mode, configured for simulating a volume of tissue activation based on each of a first one or more candidate electrode combinations, while preventing the output circuitry from transmitting the first one or more of candidate electrode combinations to the neurostimulator in response to the definition of each of the first one or more electrode combinations, and when the external control device is in the second mode, configured for allowing the output circuitry to transmit a second one or more of candidate electrode combinations to the neurostimulator.