I found an answer how to fix it by doing my own serialization. I have
translated it from C++/CLI (C++.NET) into C# and but only tested with
C++.NET (remember the right namespaces!!!!!)

List<int> l;
for (int x=0; x< 10; x++)
  l.Add (x);

Serialize:
  Stream s = new FileStream("foo.soap", FileMode.Create,
FileAccess.Write, FileShare.None);
  SoapFormatter sf = new SoapFormatter();
  sf.Serialize(s, l.ToArray() );
  s.Close();

Deserialize:
 Stream s = new FileStream("foo.soap", FileMode.Open, FileAccess.Read,
FileShare.None);
 SoapFormatter sf = new SoapFormatter();
 int[] tmp = (int[])(sf.Deserialize(s));
 l = new List<int>((System::Collections::Generic::IEnumerable<int>)
tmp);
 s->Close();

A generic List<int> inside an object:
[Serializable]
public class Test: ISerializable
{
public  List<int> l_ = new List<int>;
public Test() {
    for (int i = 9; i>= 0; --i)
    {
        l_.Add(i);
    }
  }

internal Test(SerializationInfo si,  StreamingContext context) {
              int[] tmp = int[](si.GetValue("l_", typeof(int[]) ));
              l_ = new
List<int>((System::Collections::Generic::IEnumerable<int>) tmp);
 }
public void GetObjectData( SerializationInfo info, StreamingContext
/*context*/ )
 {
     //SerializationInfo - essentially a property bag
     info.AddValue("l_", l_.ToArray(), typeof(int[]));
     Type t = this.GetType();
     info.AddValue("TypeObj", t);
 }
}