Newbie with a few questions.

[Kikaro]

I just started playing a few days ago and i'm loving the game so far.

My first questions is why aren't their underwater maps? The mechanic in their for swimming, and you can shoot under water, so why not?

My second question is how do I play on my custom map? I've finished it and want to play solo with some bots. A step by step listing would be nice.

And my final question is how can I have my character in a custom character skin I have made?