Sorry, I just got the notice of your posting, I guess it was stuck in moderation ...
The plug-ins are launched by LNS on the comptuer where LNS runs. The web interface just triggers that launch. In order for that to work, the web browser (I recommend IE for trying that out, though Firefox should also work with SmartServer 2) has to run on that same computer as well. You cannot put a link to a plug-in in i.LON Vision. That does not really make sense because plug-ins cannot be accessed via the web, you have to sit in front of the computer where they are launched. Plug-ins are very different things than web pages. The plug-in launching feature of the web pages allow you to use the web UI as a replacement for LonMaker or other network management tools. You can do almost everything from the web UI that you can do with such traditional tools. However, plug-ins are no web entities and if you want to use them, you have to follow their rules.
Yet many plug-ins do nothing else than visualize or allow changing certain data point. You can design i.LON Vision pages that cover that functionality. You can write one web page that applies to each object (e.g. functional block) of a given kind. That web-page can be made to automatically be shown if the respective objects are clicked in the auto-tree and you can place links to them. In effect you'll have to re-write the respective plug-in for the web though. And you'll probably not be able to design web pages that replace plug-ins that reprogram the respective device (some plug-ins change the cod, XIF file and program ID of their devices).