It is not yet available in VS2k10.
"First of all, thank you to those customers who have offered feedback regarding how your work and productivity are impacted by Integration Services (SSIS) not yet being available in Visual Studio 2010. As developers ourselves, we certainly understand the frustration you have reported in having two Visual Studio instances installed and maintained on your development machines. While this side-by-side configuration works, it is certainly a less ideal solution to operating SSIS from within VS 2010. Unfortunately, the staggered ship cycles of the two products (VS and SSIS) and some convoluted dependencies did not allow us to reunite the development environments of both tools until the next version of SQL Server.
Meanwhile, please be assured that SSIS projects continue to be supported by Visual Studio both now and into the foreseeable future. Until the next version of SQL Server, we will be happy to discuss with any Visual Studio 2010 customer ways in which they can optimize the interoperability of VS and SSIS. We apologize for any inconvenience and are committed to improving your user experience both now and in the future."
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