Right... In Advance Map, there is a tool called Block Editor. Open that. Now, edit the pallette into the one that you think fits the tiles you want to insert. Under the menu Picture, select Save Tileset. Open the Tileset in Paint and add your tiles. Recolour the tiles to fit the pallette that you saved the Tileset in Save it. Go back to Block Editor and got to the menu Picture, and Load Tileset. Voila. If you need anymore help, ask me when you get there.