Creating Atlass from custom texture

[hellwalker]

Hello, Is it possible for me to create ngui atlass from custom texture?

That is I want to pack all my art myself in photoshop into one texture, then use ngui to slice it into buttons.
I want to slice it by hand.

Can I do this with ngui?
And if yes how?

Thanks in advance
(I would really prefer doing it this way for current project for many reasons).

[ArenMook]

Import the texture as a sprite sheet, then define all the sprites within like you would if you were making a Unity 2D game. Use UI2DTexture to draw the sprites (ALT+SHIFT+D).