found the solution , did'nt know it was way to easy to create a vhd using DiscUtils ,
the code somehow looks like this
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using DiscUtils;
using DiscUtils.Fat;
using DiscUtils.Vhd;
using DiscUtils.Partitions;
using System.IO;
namespace VirtualDrive
{
class Program
{
static void Main(string[] args)
{
long diskSize = 100 * 1024 * 1024;
using (Stream vhdStream = File.Create(@"D:\mydisk.vhd"))
{
Disk disk = Disk.InitializeDynamic(vhdStream,Ownership.None,diskSize);
BiosPartitionTable.Initialize(disk, WellKnownPartitionType.WindowsFat);
using (FatFileSystem fs = FatFileSystem.FormatPartition(disk, 0, null))
{
fs.CreateDirectory(@"TestDir\CHILD");
}
}
}
}
}