For someone who has the same issue here is the solution: https://stackoverflow.com/a/17829842/2882534
Just create a subkey named whit your Url plus port(ex: http://localhost:54895
) at the HKEY_CURRENT_USER\Software\AppDataLow\Software\Microsoft\Silverlight\Permissions
After that, create a registry named WebcamAndMicrophone with DWORD and value 11.
Shazan! The silverlight dialog is not more necessary.
Tutorial to manipulate registrys: http://www.codeproject.com/Articles/4808/All-you-wanted-to-know-about-the-Registry-with-C-P