It seems the Character Assembly cannot be accessed from Maxscript, well it can, but the access is limited to useless things like the icon size, etc. Can I query, add, or remove bones from the Character members list? Or can I set, assume, or enter Skin pose Mode? (I looked and this does not appear to be the normal ‘skin pose mode’ from max. (AssumeSkinPose() doesn’t work with it)
CE
The usefulness of the character assembly ends long before you try to get access to it with max script. It is really only a group head wuth a UI. To add and subtract items they need to be grouped to the assembly, this is really just linking them to it. If you have a hierarchy of objects only link the root of it to the assembly.
Personaly I wouldn’t use it at all and write your own system. If you want to use Set Skin Pose and other tools you don’t need to have a character assembly in the scene. Just select all the objects in the rig and use the tool from the character drop down menu.