DataGrid: Anyone know how to resize Row Details after it's been opened?

I would like to call out to a web service asynchronously to get the row details for Datagrid.  I've got this working, except there's one little problem:  the row details does not expand to the size of the new data/controls that I've created in it after the async web service call has finished.  The row details keeps the size of whatever was in the RowDetailsTemplate.

Any ideas on how I can expand this out after I've changed the controls in the DetailsElement?  I've tried setting Height, calling UpdateLayout, etc., and nothing seems to do the trick.

Thanks.

 
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