I have just migrated a project from SSIS 2005 to SSIS 2012
Apart from the project, I had a custom pipeline component, which was also migrated to .NET 4.0, and installed in SQL Server DTS directory and the GAC, as usual.
After the migration, when I tried to open and configure the migrated component I got the error: "Value of null is not valid for stream".
The error only happened in "SSDT for BI" of VS 2012. When I tried to open and use the component in SQL Server Data Tools (VS 2010, not 2012, shell) it work without flaws.
So, this is a problem exclusive to SQL Server 2012 SP1 and SSDT for BI for VS2012