Business Intelligence Development Studio 2010

Ideally, I want to make SSDT/SSIS packages on my desktop PC that I can test and deploy to a production server environment. On my PC I have: Windows 7 Visual Studio 2008 Visual Studio 2010 (shell) SQL Server Express 2012 (local dev copy of prod) [supposedly] BIDS (Business Intelligence Development Studio) and SSDT (SQL SErver Data Tools) etc.

On my production server I have: Windows Server 2008 SQL Server 2012 Visual Studio 2010 (shell)

I cannot load/run SSIS (SQL Server Integration Services) onto my machine because SQL Server express doesn't allow for it, as suggested by these articles:

And I am getting this error when trying to look at a "package.dtsx" file in VS:

Microsoft Visual Studio is unable to load this document: To design Integration Services packages in SQL Server Data Tools (SSDT). SSDT has to be installed by one of these editions of SQL Server 2012: Standard. Enterprise. Developer, or Evaluation. To install SSDT, run SQL Server Setup and select SQL Server Data Tools.

When I run the SQL2012Express installer, it says SSDT is installed already.

Question #1: But why can't I just point a local VS2010/SSDT/SQL2012Express at my production SQL2012 environment? (Microsoft is getting their money legitimately!)