The NetAdvantage Suite for .NET is indeed compatible with the Visual Studio 11 Beta. You may, need to load the NetAdvantage assemblies for controls outside of .NET 4.5 Framework manually before they are made available in the VS11b toolbox; CLR4.0x assemblies will likely populate their associated controls in the VS11b toolbox if Infragistics 11.2 CLR4.0x was previously installed.
I have included a link below to a blog authored by our Director of Product Management, Jason Beres; which will be updated regularly with further developments related to the NetAdvantage Suite and the VS2011b.
Getting Ready for the Visual Studio 11 Beta:http://blogs.infragistics.com/blogs/jason_beres/archive/2012/02/23/getting-ready-for-the-visual-studio-11-beta.aspx
Sincerely,Chris KDeveloper Support EngineerInfragistics, Inc.www.infragistics.com/support