To export iClone motion adapted to Maya characters, you are suggested to characterize Maya character for iClone first so you can generate motions to match the bone structure (How to import Maya character to iClone?). You may use the "Motion Puppet", "Direct Puppet", "Edit Motion Layer" and "Device Mocap" to create new motion clips for the character converted from Maya. Then, you can "Collect Clip" and save the motion clip (iMotion) from from the Timeline.
In 3DXchange5 open your character converted from Maya. Import the iMotions you just created to the "Motion Library" and "Add to the Perform Editor". Then you can export FBX animations from the source motions in the "Perform Editor".
Go to "File" >> "Export to other 3D format" >> "FBX". Select preset as "Maya" in FBX export window. Tick basic setting on "Geometry" and "Animation".
Open the origin character in Maya. (Please make sure there's the same character structure with Non-Standard Character). Import the FBX file from 3DXchange5. Select "File Content" as "Add and update animation" and tick "Animation".
The origin character would be loaded animation via FBX import with motion keys automatically. (Please upgrade FBX plug-in to 2012.2 version at least)