Probably juniperus horizontalis 'Wiltonii'.

Yes , you are right. I got confirmation from another site where I put this question , before I put it here. The answer on the other site I got earlier today. Thanks for the answer , and asuring me 100% that this is "Wiltonii". I was starting to lose hope that I will identify my plant , because the days were pasing by , and no answer. I will write a blog about developing of this plant.
I am working on it at the moment , so I will in the next days show my development pics.
When I was repotting it , as the plant was deeply planted , and some branches were coming out from the ground , as I asumed , I found that three branches were rooted. So , now I have four plants , and most likely , I will continue development of two rooted branches , now new plants , as the main tree (mother tree). The third one will be given to some of my colegues from Bonsai association "Belgrade" , because I do bonsai about 7 years.