disconnected DataSet multi-threading question

[Alina]

Hello

I'm working with a disconnected DataSet and I wish to make thread-safe the
"add new rows" method.
I try like this, but does not work:

public class MyXmlDataDoc
{
.....
System.Threading.Mutex m = null;
m = new System.Threading.Mutex(false, "NoPassingAdd2");
m.WaitOne();

this.DataSet.EnforceConstraints = false;
//add rows throgh the xml methods...
this.DataSet.EnforceConstraints = true;

m.ReleaseMutex();
.....
}

Could somebody give me a hit or an example how to do it (multi-threading)?
I do not wish to put a lock.

Thank you