How can I add a custom autocomplete list to redactor?

[rhodes]

Hello,

I would like to add a custom autocomplete list to redactor. Currently there are two autocomplete lists in action.

1. If you type @ followed by some characters a list of user suggestions appears
2. If you type # followed by some characters a list of tag suggestions appears

Now I would like to introduce a third list which could start with $, for example. Within the autocomplete list shown to the user I would like to list items fetched by a REST service.

Any ideas where to start?