well a Heirachy IK setup is a bone setup (IK is specific to bone animation) ... that aside, you said you were using the Panda DirectX exporter - not the Microsoft DirectX Exporter ...
It sounds like something has been rigged incorrectly, because without touching anything - i can create 2 box's animate them to the 30frame limit just spinning and it exports with... 30frames
however the interpol values are set to about 1/4 speed for some odd reason, still exports fine.
So if i were you i'd backtrack what i've done.
As i explained before the exporter is exporting excluding the interpol so this is why your getting so many frames because its premaking them to the interpol.
now i'm unsure why YOU can't seem to be grasping what i have been saying.
Tsu'va Oni Ni Jyuuko Fiori Sei Tau!
One block follows the suit ... the whole suit of blocks is the path ... what have you found?