Be very careful with Poser IK; it is onlya partial implementation at best. Something like bellydance hip lifts can be difficult to keyframe, as you have to be aware of exactly what is going on. Most hip action starts at the feet, since that's where the weight is being supported, and involves all the joints up to the end of the lumbar chain.

This is an example of why I say we need a full IK/FK system. Poser only supports IK; with FK you could reassign a target at any joint, so you could designate the top of the belly bending as an anchor to get the basic motion down in hips and legs, then turn it off so the rest of the body is affected by hip action. As it stands now, if you animate with IK in Poser and then turn it off, you can have some serious issues, particuarly if you used quaternions. Although it can be amusing for others to watch your figure turn into a mesh knot monster.