Problem solved thanks to marcin_j:
Your code looks find (well,... you mispelled HANDLE), you can use procexp.exe from sysinternals to find your HANDLE by name (if it is not found then it was closed), also observe on Performance tab how Virtual Size of you app changes, there is also Handles count that should change accordingly.
Also, observe what will happen after you execute memset(buffer,0,size); after MapViewOfFile - this is actually when system will commit memory and when your workin set will rise.
My above comment is wrong, CreateFileMapping by default applies SEC_COMMIT which commits memory. But I suppose your memory is paged until memset is called, after that call paged pages are moved to physical memory, which rises working set.... if I am not wrong...