When can i use EF4's 'Include FK Columns in the Model'?

I'm a little confused about EF4, and the EF homepage doesn't help me.

1. Is EF4 a separate download or is it a part of VS2010?
2. What version of EF is native in VS2010?

The reason I'm asking is because I created a .Net 3.5 project in VS2010 (.N开发者_如何学编程et 4.0 is not yet on the production server) and when I went to check the checkbox 'Include FK Columns in the Model' it's gray and says I cannot use it. Is it because of me targeting 3.5, is my EF version maybe not 4.0?

is EF4 a separate download or is it a part of VS2010?

 Its a part of VS2010 only

.Net 3.5 project in VS2010 - But also it creates for Version 1 of Entity Framework

if you go with .Net 4.0 in VS2010 - the second version of Entity Framework is used there.

Note: there were some problems in FK on the Version 1 of Entity Framework