It has come to my knowlege that converting meshes is just a way to change the file type. There's no tutorials for it, because I believe that you must downlaod an extra program to convert certain files. I'm not exactly sure of what that program is, but I do think you may able to save Blender creations into the correct file format for Fh.
When you go into Blender, Open your project and save it in the .MESH file type.
You may also google the OGRE command tools, i believe that will do it for you if you can't save in Blender.
I haven't had much experience in Blender, so I hope my information is accurate.
-Cosmic