@markschum,

It seems to be hard coded in Poser. I changed the internal name of 'liftarm' to 'lHand', and its endpoint got displayed  as numeric fields in the Joint Editor, and it also got the red cross-hair.

Although it's a major ball ache to rename parts, adjust the endpoint cross-hair, then change the name back, at least it can be done, and is probably feasible if you only have two or three parts to process. You need to be careful not to rename the geometry group in the declaration section.

actor lHand:1
    {
    storageOffset 0 0 0
    geomHandlerGeom 13 liftarm [don't rename this]
    }