From Rockford Lhotka's Expert C# 2008 and VB 2008 Business Objects books
Hi Anthony,
The BusinessListBase does not MarkAsChild.
You need to construct your child objects as children.... that is, you need to use the Child_Fetch method (which will mark the object as a child), or call MarkAsChild explicity in your constructor (if you are not using the child dataportal stuff).