how to ctrl + shift + f3 on windows using boot camp

Hi people:

I recently receive a MBP mid 2K11; with Yosemite. Last weekend I upgrade to "El Capitan" OS and now I'm using bootcamp 6.X to install Windows10.

I need to test some customization to Windows; and therefore need to enter on OOBE; using CTRL + SHIFT + F3 keys. Since the windows bootcamp utility haven't been ran; I can't find the correct keystrokes on the MBP keyboard to use OOBE..

Does anybody know to to issue that keystrokes on a MBP keyboard when running initial installation phases?

Thanks by any help...

PD: Yes I have tried command + shift +fn +f3 or command + shift +f3 and more combinations without luck.