Is There A Microsoft Document Exchange And Database System Like Lotus Notes Or Oracle Managment Content?

Hello,

I work for an attorney staff, so basically the whole day they are
sending themselves a lot and a lot of papers (Word docs or Excell
sheets).

We are going to propose them the use of a Document Exchange and
Database System (like Lotus Notes or Oracle Managment Content,
formerly known as Internet File System IFS ) with .NET interfazes.
Basically the idea is that instead of sending papers the whole day,
they can use a software to check and manage more quickly their
documents.

We are looking for a system that allows us to manage:

- Security
- Versioning
- Folders
- Check-in/Check-out
- Workflow
- Search and Retrieval
- Extensible Metadata

My question is:

1) Is there any Microsoft tool who can help us to achieve that
(management of codes, dates, text, names of documents- I mean like a
Document Exchange and Database System) with .NET interface?

2) Or do we have to built it from scratch?

Thank you very much!
Jorge