I get an error
Abramoff has updated the utility. We need a test. 
and maybe we will do an automatic "Сutter".
Done. This feature is added in Retimer.
Wow thanks Kva & Abramoff! Same
DL link?

I did this trigger animation today in 10 minutes with Retimer. I use it for a lootable ponya corpse.
A but you are not telling the whole story

you first had to make a ponya mesh where he is lying down! Then did you have to make a new .skeleton first or did it export with the mesh?
you first had to make a ponya mesh where he is lying down! Then did you have to make a new .skeleton first or did it export with the mesh? 
Well, you do not need a mesh/skeleton with this pose, all this makes the animation in frame 0.
A but you are not telling the whole story
I can tell you how I did it.

I used die1.skeleton animation (Ponya_M certainly).
1. Open die1.skeleton.xml
2. It is necessary to find the right section of frames. We need 0.833333 - 1.33333.
3. Remove unnecessary frames (keyframe time= 0 0.83) [Cut]
4. Then we change time [Action] - 0.833333 [Run]. Now the 0.833333-frames turned into 0-frames.
5. Then make the animation longer: [Action] * 2 [Run]
6. Then change all 0.86668- frames without the previous frame. Like this:
<tracks>
<track bone="Bip01">
<keyframes>
<keyframe time="0.86668">
<translate x="0" y="0.876139" z="-0.184561" />
<rotate angle="1.56748">
<axis x="1.16416e-008" y="-1" z="3.77188e-008" />
</rotate>
</keyframe>
<keyframe time="1">
<translate x="0" y="0.876139" z="-0.184561" />
<rotate angle="1.56748">
<axis x="1.16416e-008" y="-1" z="3.77188e-008" />
</rotate>
</keyframe>
</keyframes>
</track> Turn it into 0 manually.
<tracks>
<track bone="Bip01">
<keyframes>
<keyframe time="0">
<translate x="0" y="0.876139" z="-0.184561" />
<rotate angle="1.56748">
<axis x="1.16416e-008" y="-1" z="3.77188e-008" />
</rotate>
</keyframe>
<keyframe time="1">
<translate x="0" y="0.876139" z="-0.184561" />
<rotate angle="1.56748">
<axis x="1.16416e-008" y="-1" z="3.77188e-008" />
</rotate>
</keyframe>
</keyframes>
</track>This is done for smoothness, but not necessarily.
7. Then I changed(manually) the trajectory for Bip01 bone - for body gliding (y coordinate).
<track bone="Bip01">
<keyframes>
<keyframe time="0">
<translate x="0" y="xxxxxxxxx" z="-0.184561" />
<rotate angle="1.56748">
<axis x="1.16416e-008" y="-1" z="3.77188e-008" />
</rotate>
</keyframe>
<keyframe time="1">
<translate x="0" y="xxxxxxxx" z="-0.184561" />
<rotate angle="1.56748">
<axis x="1.16416e-008" y="-1" z="3.77188e-008" />
</rotate>
</keyframe>
</keyframes>
</track>to
<track bone="Bip01">
<keyframes>
<keyframe time="0">
<translate x="0" y="0" z="-0.184561" />
<rotate angle="1.56748">
<axis x="1.16416e-008" y="-1" z="3.77188e-008" />
</rotate>
</keyframe>
<keyframe time="0.6">
<translate x="0" y="0.1" z="-0.184561" />
<rotate angle="1.56748">
<axis x="1.16416e-008" y="-1" z="3.77188e-008" />
</rotate>
</keyframe>
<keyframe time="1">
<translate x="0" y="0.1" z="-0.184561" />
<rotate angle="1.56748">
<axis x="1.16416e-008" y="-1" z="3.77188e-008" />
</rotate>
</keyframe>
</keyframes>
</track>I added 0.6 frame to pause gliding before the animation stops.

8. Change name="Die1" to name="On" and Save. Animation is ready.