How to fill up space with the new grease pencil tool blender 2.78 (early version) just as the title says how do i fill up the area i want to ?


because the only way i could get a bigger brush (the only way with grease pencil is by making the pixel bigger (it could only get up to 10 pixel) and it would certainly be a repetitive and not so effective way to do it) sorry if the question is not too clear, i've just get back from work and i'm not at the brightest of time :] 

EDIT :

as per suggestion i am editing the question to how can i fill up the space with texture or any other shape that will be able to fill the spaces + on how can i specify where will i fill it up :D
Press N to show the properties region in the 3DView and expand the Grease Pencil panel to find the colour and opacity settings for the fill.