Hi turbo2000,
I'm far away from being MR material expert, but here is what I can tell you.
1.
2.
To make such map you need to simply convert diffuse map to grayscale
3.
4.
IMPORTANT!: All the maps you want to use need to be RGB since MR will not work with grayscale maps (yet).
I strongly suggest to read MR manual first since there is a lot of info about proper approach in making MR materials.
BTW, your map is not seamless.
HTH, below is my quick try.
I'm far away from being MR material expert, but here is what I can tell you.
1.
2.
To make such map you need to simply convert diffuse map to grayscale
3.
4.
IMPORTANT!: All the maps you want to use need to be RGB since MR will not work with grayscale maps (yet).
I strongly suggest to read MR manual first since there is a lot of info about proper approach in making MR materials.
BTW, your map is not seamless.
HTH, below is my quick try.
hi tigr thanks for helping! can you explain how you did the maps or even better make them so i know how they should look? I have made a tile-able texture here http://www.lusica.dk/Mursten-diffuse.jpg wich i would like to make bump and roughness maps for. Any help is appreciated 
Sure I could just send you the maps but I think you'll benefit more if you try to do it yourself. It is 5 min job and next time you will need no help.
I have no CG background, I'm rather hobbyst so my approach might be wrong but still, it works great in everyday archiviz and only that matters.
Quick intro:
For making 99% of architectural materials those three maps (Diffuse, Bump, Specular/Roughness) are all you need. Sometimes it is enough to place only Diffuse map in every slot (this is how we do LW's materials) but it would be a shame to have such advanced renderer and not use it potential.
So why to make 3 different maps for one material? So you can control every aspect of your material separately.
1. Diffuse map - colour map of material. Make sure it is seamless and does not have any noticable shadows (like 90% of free textures have) Otherwise it will look fake if the lighting direction/power won't match the one in the map.
2. Bump map - grayscale version of Diffuse map. More gradients = stronger bump. To do such a map you need to go to:
Image -> Mode -> Lab Colour -> Grayscale -> RGB
Now you can use PS tools to clean some areas and alter others. Here the most bright should be the brick face and the darkest - mortar.
3. Specular / Roughness map - altered version of Bump map. More white = more specular. Now it is up to you what areas and how much reflective you need'em to be. Usually I do this:
Ctrl+L (levels) -> move left slider a bit to the right / move right slider a bit to the left -> judge the preview. This will add more contrast to the map and alter the reflective areas of the map. Roughness map is usually inverted version of a Specular map, so you don't even need to make one, Maxwell has such option on the fly.
Hope that was clear enough. Have fun.
I have no CG background, I'm rather hobbyst so my approach might be wrong but still, it works great in everyday archiviz and only that matters.
Quick intro:
For making 99% of architectural materials those three maps (Diffuse, Bump, Specular/Roughness) are all you need. Sometimes it is enough to place only Diffuse map in every slot (this is how we do LW's materials) but it would be a shame to have such advanced renderer and not use it potential.
So why to make 3 different maps for one material? So you can control every aspect of your material separately.
1. Diffuse map - colour map of material. Make sure it is seamless and does not have any noticable shadows (like 90% of free textures have) Otherwise it will look fake if the lighting direction/power won't match the one in the map.
2. Bump map - grayscale version of Diffuse map. More gradients = stronger bump. To do such a map you need to go to:
Image -> Mode -> Lab Colour -> Grayscale -> RGB
Now you can use PS tools to clean some areas and alter others. Here the most bright should be the brick face and the darkest - mortar.
3. Specular / Roughness map - altered version of Bump map. More white = more specular. Now it is up to you what areas and how much reflective you need'em to be. Usually I do this:
Ctrl+L (levels) -> move left slider a bit to the right / move right slider a bit to the left -> judge the preview. This will add more contrast to the map and alter the reflective areas of the map. Roughness map is usually inverted version of a Specular map, so you don't even need to make one, Maxwell has such option on the fly.
Hope that was clear enough. Have fun.
Thank you for your time tigr! i have been experimenting with it, and now my photos look very nice!
Glad I could help. Don't hesitate to post your results, and I will get myself a beer. Cheers 
