From what's been said it's doesn't have to obvious like the map that were done as 'showcase' maps with the massive VIA logo as brushwork. They just need to be 'somewhere', maybe even like the dopefish or that character on the underside of Q3DM16 - you only see it when you fall off.
If you've been having problems getting the logos or prepping them for use for the competition, you can now get a 'ready to use' pack from a download mirror I've added to me site. It's the only place you can get the pack atm but they'll be going up on D3W asap as well.