This isn't really my strongest side to meshes... but have you tried following this?
In order to convert or make your own mesh, you need to have the following (This tutorial was given by Alpha Eclipse, I just re-worded a few things to make things more detailed and make a little more sense):
What you need to do first is download Blender, Python, and its plugins. Note: You will need to download Blender THEN python.
Blender: https://download.blender.org/release/Blender2.49b/ (https://download.blender.org/release/Blender2.49b/) (download the windows.exe)
Python: https://www.python.org/download/releases/2.6.2/ (https://www.python.org/download/releases/2.6.2/)
and TWO Plugin links that you will need in order fo rit to work: http://www.ogre3d.org/download/tools (http://www.ogre3d.org/download/tools) (Ogre command line tools: windows download) and http://download.blender.org/release/Blender2.49b/blender-2.49b-script_bundle.zip (http://download.blender.org/release/Blender2.49b/blender-2.49b-script_bundle.zip)
Once that is complete, put the ogre command line tools in their own folder in the C: drive. For example, C:\OgreCommandLineTools. After that, export all of the files from the other plugins' download into (!!IMPORTANT!!) "C:\Users\-PC NAME-\AppData\Roaming\Blender Foundation\Blender\.blender\scripts." Make sure Blender was put into that location (Roaming) otherwise Python may not find it, and that's an issue. If it doesn't locate Python and you don't get this when you start up Blender:
(http://i57BannedImageSite/jgod9z.png)
Then refer to this link: http://www.feral-heart.com/index.php?option=com_jfusion&Itemid=2&jfile=index.php&topic=34166.0 (http://www.feral-heart.com/index.php?option=com_jfusion&Itemid=2&jfile=index.php&topic=34166.0)
Once all of that is setup, import your mesh. You'll know if the scripts are working when you see this option:
(http://i59BannedImageSite/29shed.png)
Import your mesh, (I believe a little box will pop up saying stuff with "___ images" or something about textures. Make sure that's checked so the texture is included. I would get images for this however I have no .obj with me. (if it doesn't say that, ignore what was said, it might have been for .3D files.) Once it's in Blender and you see it, you may notice that it's not textured.
Here is Alpha's tutorial about adding the mesh's texture: http://www.feral-heart.com/index.php?option=com_jfusion&Itemid=2&jfile=index.php&topic=46434.0 (http://www.feral-heart.com/index.php?option=com_jfusion&Itemid=2&jfile=index.php&topic=46434.0)
After it's done being textured and whatnot, you can export it as a .xml or .mesh file. Some Example images are here. http://www.feral-heart.com/index.php?option=com_jfusion&Itemid=2&jfile=index.php&topic=49368.0 (http://www.feral-heart.com/index.php?option=com_jfusion&Itemid=2&jfile=index.php&topic=49368.0) Make sure you use my tutorial to texture your object before exporting it however.
I hope this helps.