Love the hex sea zones. Here is something TMTM posted on doing textures and wavy lines around borders using paint.net that might get you the texture you are looking for.
I recently made a new module for abattlemap for the A&A Global 1940 http://www.axisandallies.org/forums/index.php?topic=22555.0
In it I used the same color scheme as Axis & Allies Global War, I had to figured out how to do it and I kinda did… so I thought I’d share the process with anyone wanting to do the same:
How to make the textured colors in Axis & Allies Global War Variant
First I click New and size the new canvas as 60 x 60 pixels (we are creating an image which we�ll use later to fill the area�s of your map)
Select the base color and use the paint bucket to fill the new 60 x 60 canvas
Click on Effects � Noise � Add Noise and just adjust the intensity… I did around 25, but experiment for yourself.
Click on Effects � Blurs � Average Blur and set the radius at 3
Now our 60 x 60 image should look like the textured color we desired.
Save it as mynewcolor.bmp
Now the area on your map that you want to fill with your new textured color, you�ll need to get a plugin for Paint.net. found here http://www.sapphireonline.com/Downloads/PhotoFloodFillPlugIn.zip and just unzip it to the default C:\Program Files\Paint.NET/Effects folder and close and reopen Paint.net
Now with your map open, use the Magic wand and select the area you want to fill with the new color. Then click on Effects � Photo Flood Fill and for Photo File name we are going to use the file we just make mynewcolor.bmp and click ok and now your map will be filled with that color.
How to make waves like in Axis & Allies Global War Variant
I just used Effect � Object � Drop shadow and settings 0�d the blur and only adjusted widening. You might see waves on the land area… no worry… you need to use layers for each wave and the land color layer should be on top of the wave layers and will cover the waves on the land. I also recommend that on the layer you�ll use to make wave that that layer only have the lines you�d like to add waves to… remove all border lines etc so it doesn�t add waves to those etc.
Tip: Always use the duplicated layer, so your not adding effects to your outline layer, always save the original outline layer for other effects.
I use these in my recent module for A&A Global 1940 module at http://www.axisandallies.org/forums/index.php?topic=22555.0 where I have the source files for download and you can see how I used them.