Serious Sam 3: BFE

Serious Sam 3: BFE

Custom maps, mods, skins & campaigns
Discover and download custom maps, character skins, weapon modifications, skins, enemy modifications, campaign mods, and much more. Plus, click here to learn more about creating and sharing your own mods.
Editing Skeleton file
For a project I have a (player) model I want to import to the game. due to the nature of model I need to edit the Skeleton a bit to match the proportions of the model. Matching it the other way around wont do me any good. So my question is, how can one edit the skeleton file (.skl file)?
I cant open the skeleton neither in blender nor maya lt.