If you have to target the VS 2010 shell I do not think SSDT will work for you at all. The furthest back SSDT can go back is VS 2012. It looks like MS used to have a version but no longer make it available. You will need to get BIDS from SQL Server 2008 R2 media if you want to target VS 2010.

Previous releases of SQL Server Data Tools (SSDT and SSDT-BI)

https://msdn.microsoft.com/en-us/library/mt674919.aspx