To export iClone motion adapted to 3ds Max characters, you are suggested to characterize 3ds Max character for iClone first so you can generate motions to match the bone structure (How to import 3ds Max 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 3ds Max. Then, you can "Collect Clip" and save the motion clip (iMotion) from from the Timeline.
In 3DXchange5 open your character converted from 3ds Max. Import the iMotions you just created to the "Motion Library" and "Add to the Perform Editor". Then you can export BVH animations from the source motions in the "Perform Editor".
Go to "File" >> "Export to other 3D format" >> "FBX". Select preset as "3D Studio Max" in the FBX export window. Click on basic settings in "Geometry" and "Animation".
Open the original character in 3ds Max. (Make sure there's the same character structure with the converted iClone character). Import the FBX file from 3DXchange5. Select "File Content" and "Add and update animation" and Click on "Animation".
The original character will be automatically loaded with animations, via FBX with motion keys. (Please remember to upgrade your FBX plug-in to 2012.2 version)