The way the PSD link script works is - AS references layers form their position in the Photoshop stack, from their layer position from the base layer. So, if you add layers, be sure to add layers right at the top of the stack otherwise if you add layers in the middle of the stack and save the PSD file, the wrong layer may get referenced in AS.
However, the new layers will not be added to the AS file (it would be great of they were). Instead, you'd need to re-import the PSD file, and kind of manually cobble the layers into your AS file. Can get a little confusing and nuts.
So its got NOTHING to do with the layer names - its about their position in the layer stack. Hope this helps.
thanks guys,
@selgin, I was thinking more of a scenario where you importing PSD switch layers and needed more inbetweens or a new pose after having already dome some animation in AS rather than importing a 'flat'