The latest development release of ModelConverterX has a new feature that can help in converting models between different sims. Often these simulators use different names for their animations. For example FS2004 and FSX have different names for certain types of animations. Before ModelConverterX used a hardcoded mapping when importing these models, but now this mapping has been made user configurable. This way you can control better how the animations are exported.
Internally ModelConverterX uses the FSX/P3D animation names, as defined in the modeldef.xml file. At the moment two mapping tables are configurable, one from FS2004 names to FSX names and one from X-Plane names to FSX names. The manual provides all the details on how to configure the mapping.
If you find that the default mapping table that ships with ModelConverterX is missing an animation mapping that is generally available, please post this information on the ModelConverterX forum, so that I can include it in the default mapping file in future releases.