Ckeditor plugins deletion and saving custom buttons

[clearvision]

In the process of upgrading from 3.x to 4.x. 

Working on porting our ckeditor plugin and got it installed and working as a test, but now need to finish it.  I can't find a way to delete the plugin... uploading says it exists and won't replace.  I'm I missing something?

So I can of course reset to default... BUT I also have a bunch of custom buttons thru the new Invision interface.   How do I save those?  If I reset to default it appears I lose them and have to re-enter all, that could be a major pain down the road.

As an aside not having custom BBCode left in posts is a real pain for us as we use it to insert image snapshots and the code to get those has changed and could change in the future. So far have not found a way to modify existing posts as cannot just change the bbcode and recache.  Working on a javascript solution that has to run every time a post is displayed and trigger off a class name of a span that surrounds the html that might change.  Sigh.