Techniques for steering of target poles formed by implantable electrodes in a stimulator device are disclosed. The steering technique modifies the relative amplitude of target poles once they are steered to an electrode array boundary. Once a target pole is steered to an electrode array boundary, further steering in the direction of that boundary results in a gradual decrease in the relative amplitude of that target pole. Eventually, continued steering in that direction will cause that target pole to disappear. Thus, in the case of a target tripole, continued steering will eventually cause the target tripole to be automatically converted into a target bipole. In another example of steering, target poles defined linearly in one direction can be split in an orthogonal direction to create a target pole configuration that is two-dimensional.