XWikiAttachmentStoreInterface.

In this regard, I have a few Questions:

1)If I chose this option, do I have to follow the implementaion as done for 

XWikiHibernateAttachmentStore (Is this the class that handles adding the attachments to the DB?)

2) would that be enough - just implementing the interface, so that the functions like saveAttachementContent() will add it to SVN and loadAttachmentContent() will load it into XWiki from SVN. or would I have to do something with other classes like the XWikiAction class (in the Web package)

3) Sergiu suggested that I could also use the notification mechanism for the Fileupload action. Is this referring to the UploadAction class in the Web ackage or the fileupload plugin?

I am sorry if I am being naive, I am just trying to undertsand the code structure and dependencies, call hierarchies etc. Is there any place where I can go in to understand the code better?

4) Also, my understanding is that the API package has all the classes whose objects can be used in the velocity scripts at the presentation layer. Am I right?

5) Can the SVN integration be done at the presentation layer (with velocity scripts...I doubt it, but just wanted to confirm)

6) this is something to do with Eclispe and Subclipse I guess. I used subclipse to download the xwiki core and then checked it out into my workspace. The first time I did it, I had the Lucene plugin class in there. The second time I re-did it, the plugin class was no more there. (That is just one of the classes I noticed). could you think of something I might have missed out?

Waiting eagerly for responses.

Thanks