Where is Addon registrated?

[Ronniea]

Hello,

I'am setting up a multiserver enviroment.
With a DB server, web server en mail server.

Now i had installed with Addons the Roundcube application.
(Repository: web wack creations)
Later is this server crasht en a used a backup to restore this server.
In this backup was not the roundcube application

I have two questions:

1. I see in ISPconfig that Roundcube is installed (but its not), so where is this registrated and can i delete something so i can reinstall it?

2. Can i finetune the Addon package so that roundcube used the multiserver setup?

I hope that somebody can answer my questions.
Thanks, Ronnie