To put logos on the kit, first choose strip. At the bottom should be Kit Marking. Choose Chest Logo, then scroll down to "Custom." Select "Create from Scratch." You'll have three options: Photo, Import Data, and Draw. Photo will allow you to take a picture with a webcam attached to your computer. Draw will allow you to create the logo yourself using the ingame editor. Import Data lets you open up a picture file saved on your computer. The file must be 2 MB or lower, with a max size of 640x512 pixels, and must be JPG, PNG or BMP.
This is for the PC version, mind. I'm assuming the console versions have something similar. Hope that helps.
Either that, or be a lazy bum like me and wait for someone to upload an option file with the kits updated.