[siliconbauhaus]

like you would using any other renderer.....they dont show up in the editor though but they will in the viewport

[Aldaryn]

Just use the Maxwell sahaders, and add texture maps as you would with any other shader you've been working before. And use the "Show map in viewport" button in the bitmaps level in the material edittor to display that map. The bitmap I/O plug is independent of the maxwell shader, so, it works just like it worked before with any combination you've used it.