The problem is not not make the ages work in multiplayer - many of the ages we currently have don't have any functionality which could be critical in a mutliplayer environment, and from the 10-15 ages that have more or less complex puzzles, most work fine in a multiplayer environment.Because, honestly, that's what we all want most with our fan-created ages right now - we want them to work in multiplayer.
The blocker is not multiplayer compatibility, but the MOUL format being different from the POTS one. Since Blender -> 3ds Max -> Cyan's plugin is not going to work well, the key is to add MOUL export to Blender. The best route to this goal seems to implement a plugin based on libHSPlasma since the MOUL write capability is already implemented there, and it has a Python interface. But there is no way a tutorial can be written at the current stage, it's software that needs to be created (and it might even be too early for that since Blender 2.5 is still in alpha stage).
But this is just to export an age from Blender into the MOUL format. To make it actually work in MOULagain as you are writing, we first need a procedure set up by Cyan to get a fan-created age on there. Some people managed to get a very simple and basic test age exported in MOUL format, but currently there is no way to get it online. Again, no way a tutorial can be done here before Cyan tell us how they want this to happen - or, the way I would prefer, they give us the source to run a server on our own
