Well, because I have custom Textbox (EditText etc.) with custom font, and custom behaviour (when it's too big, font changes size to fit textbox) it is really time-consuming to make 3 custom controls for 3 platforms.
I figured, that I can show platform control "behind" my game with opacity 0.0 (just in case), focus it and show keyboard that way. Then I subscribe to "TextChanged" and view it in my game. When I don't need it i just loose focus (and hide keyboard).
I realize that this is not very proffesional aproach, but it works... What do you think about this?