Unfortunately Anim8or does not have boolean functions (yet), which allow such things as object merging and shaping one object with another. The only real alternative is point editing, as $imon has pointed out. It can be a little daunting at first, but once you have the hang of it it opens up a whole new scope of possibilities. It's well worth learning, because point editing of wireframed objects is really the most fundamental level of 3D modelling. Primitives and parametric objects (extruded, lathed, etc.) are really just mathematical shortcuts, allowing quick construction of wireframe objects. Moving from primitives and parametric modelling to vertex (point edit) modelling is the equivalent of moving from building blocks to sculptor's clay.