Storing documents in Database vs CMS in JSF, Seam, Hibernate application on cloud

Question

I am about to start with an application using JSF 2, Seam 3, Hibernate and Hibernate search with the following characteristics:

• Users will be uploading documents (pdf, doc).
• There can be millions of documents.
• The application will be deployed in the cloud.

Here are my questions:

1. What will be the best place to store the documents: a database or a content management system (CMS)?
2. If choosing a database, should I go with document oriented db?
3. Is there any integration between Hibernate and document oriented databases or CMS to fetch the documents and index it in Lucene?

Basically I am looking for an approach that will be good for storing documents in the cloud, easy accessibility of documents for indexing and keeping performance in mind.

Any suggestions / experience or link on this will be good.