I assume you are trying to convert a BFP model for use in ESF right?
It is quite possible and i have done it a few times.
Here's a quick tut on how to do this in ms3d.
*Firstly the model is usually divided into 3 parts ,eg...Head...Torso...Legs
*Each part has a corresponding skin (one skin may cover more than one part)
*The skins are usually in *.tga format
*When importing mdl's into milkshape you'll notice the strange pose that they are in.
You'll have to either manually correct it (the hard way) / or use a mdl based animateing program to export the model part in a more suitable or its original pose.
*Now lets say you've done all of the above, now you need to merge all parts together into one ms3d then attach all of the parts to where they should go. ie legs to torso to head.
*Then lets see, you wanna make sure the model is in a suitable pose for the skeleton you're going to be assigning it too. Assign the model and save the resultant .ms3d
*Now the skins, open up each skinmap in a prog such as photoshop, set the color's to 256 indexed, then save as .bmp. Throw those skins into the same directory as your ms3d.
*Finally open up your ms3d , make sure that the materials are pointing to the correct skins (your new bmp's) then export to .smd and overwrite the reference smd of the esf character whose skeleton youve assigned the new model to and whose anims you'll be using.
*Select compile .qc and select the qc file in your working directory.
If all goes well with the assigning everything else it should work.
Questions?