I've made an assembly A2S that is symmetry of an other one A1.
Parts geometries are updated automatically.
However, when I had components in A1, they don't appears in A2S.
So, is it possible to update A2S for new components in A1 would be added in A2S ?
To my knowledge, this is not supported. You have the option to make the copied geometries dependent, but any components added to the master assembly afterwards, will not be added to the copy.
The dependency will be applied upon copying and then the regular reference mechanisms will do their magic during regeneration.
An update mechanism would require a dialog similar to copying to come up again, to enter names for not-yet existing components, which could be implemented.
However, you can modify the copied assemblies and for example add other components and remove some of the original ones. How should the update mechanism deal with this situation?
Even if there is a good, bullet proof concept, it looks like a lot of extra programming for a rather sparsely used functionality.