I'm in desperate need this mod because if I had already bought it to use s2.
sorry my bad english

The closest you will get, unless the insim owner sees and decides to share his source with you, is this: http://www.lfsforum.net/showthread.php?t=43103
(This is an actual source code. Not a ready-to-use out-of-the-box application). So, you need at least basic understanding in C#.

I am telling you this now, so you can stop wasting your time (really, that's all you can possibly do) - there is no other way of obtaining what you are looking for specifically - no other way, than knowing the programmer, or the owner of the server. Instead, you may get yourself into coding, or start a server with a programmer (I would advise you to ask your friends first, if there are programmers amongst them).

If you want to get into programming yourself, please reply, and I'm sure someone, or me again, will reply back telling you the first basic steps.

Quote from Polaco_Drifter :

I had already bought it to use s2.

Not to sure what you are trying to say but one thing is demo users can use insim it is not restricted to s2 players