How to have 2 skin for the same model?

Let say I have a normal marine and a skined marine into a medic. In my map I need both of em. How can I do this using import manager(dont want any WinMPQ or similar program). I didnt find any tutorial on how do this.

Please link me to the download page of the program I need (if I need)

I have image extractor 2 and photoshop 6.

PS: If I set the custom path of my medic to the marine, I wont have anymore the marine. need both remember?

Thank in advanced

I tryed but that doesnt worked. I export/import the marine model and tryed changing the skin of the second marine but both of em had the same skin. Because they use the same model even if I attach it to another unit.

Let say i want to replece the footman with the marine model. I export/import the marine model. I set custom pathing to the footman pathing. That work both have marine model. Now I import the medic skin and set the pathing to the footman pathing. Nothing happen. If I set the pathing to the marine both will have same skin.

What can I do?

it involves very basic .mdl editing, masterslowpoke has a tutorial of how to do it on his site, which i wish i knew the link for :/.