I have recently seen an issue that popped up in a couple different projects I have worked on.
When using a wizard inside Visual Studio, the available datasets list has been empty. I was able to solve this once after exhausting other build/rebuild techniques by creating a new project, then copying all the source files from the orginal project.
I’m really not sure where the orginal error was in the project, but the same thing happened today in a different project. Rather than creating a new project, I read in this post you could create an ‘index.aspx’ and recompile – it worked!
I’m not sure if this is a bug, but if you get the scenario where your business objects are not available as options in a VS wizard, try adding an index.aspx and let me know if it works…