Okay, I am not exactly sure about this but I think I know how it could work.

First things first, you will need mikshape and the new mesh editor.

Convert the general you want to the ms3d format using the mesh editor.
Convert a unit that has a sword. (say dismounted fuedal knights)
Delete all of the animations for the general.
Copy and paste all of the animations for the dismounted knights to the dismounted general.
Repeat for all of the lod's.

Then I think you simply go into the Unit_descr and Model_db file and edit the horse out.

Alternate, edit the horse out in Unit_descr and Model_DB, use animation set from dismounted feudal knights.

Might want to increase hit points to three or increase unit size to 30 in the Unit_descr file.

May not work. Have not tried it myself. Look at the "How to Add a Unit" tutorial to see what I am talking about.