Detaching Entities in EF4 - losing object graph

Question

As other questions have noted, when you detach and re-attach an object, any child objects are gone. I thought doing this:

db.Properties.MergeOption = System.Data.Objects.MergeOption.OverwriteChanges;

would cause subsequent reads to fully repopulate the object and graph when it was read in, but no such luck. Is there any way to get this to work?

Specifically, I'd like to be able to detach an object, then re-read the object in from the database with the child objects all there.