Need more info.
I assume (hah) you are using List. This would make it so much easier for you.
List<byte> mybytes = new List<byte>();
mybytes.add(dabyte);
You can then lay down the foreach
DataTable dt = new DataTable();
dt.Columns.Add("dabyte", byte);
foreach (byte b in mybytes)
{
dt.Rows.Add(object[] {b})
}
dt.WriteXML("C:\dabytes.xml");