Modding

Hey everyone, is there a thread somewhere that discusses how to extract a building model from the game and then (after some manipulations) export it back into the game? Even if it's just a brief overview.

I mean, you extract it from the game, edit it, and then put it back in. The "extraction" and editing stages are fine, but the game won't accept the model back in. Loading it with .mb doesn't create a skeleton in the editor, and simply replacing the file with an equivalent UID in gr2 format just makes the model disappear.
It feels like it's easier to import some random model from the internet, strangely enough.

P.S. I'm exporting to gr2 from Maya 2006, using the default settings for geometry, with the Global bone and coordinates set to 0. Before that, I convert it to wrl - obj - import into Maya. Everything seems to be working correctly up to Maya.
In short, I was able to work with creature animations, fix them, replace files, and change the animations of existing units, but I'm stuck with buildings.
I've checked everything related to creature models, and I've also watched Mr. Estonets' guides on YouTube.