HI Naag,

if you would like to add them in Visual Studio toolbox I am afraid it will not be possible if  your website is set to run under .NET 4.0, however if you have website running on .NET 2.0 or 3.5 NET Framework and the controls are already there and you change the runtime of the website to .NET 4.0 the controls should work.

Is this what you are trying?

you can check how to add the controls to  VS Tollbox :

http://help.infragistics.com/NetAdvantage/ASPNET/2011.1?page=Web_NetAdvantage_Web_Client_ASPNET.html