There was film of Virgie at the unmarked grave of Daniel. Definitely inground burial.
I did find this...
A fake headstone placed on Anna Nicole Smith’s son’s grave.
Posted by Capri on February 10th, 2007
http://nosysnoop.wordpress.com/2007/02/10/a-fake-headstone-placed-on-anna-nicole-smiths-sons-grave/
this also may go with it also... (slow loading pages)
http://www.splashnewsonline.com/2007/02/10/2593/
http://www.splashnewsonline.com/2007/02/09/anna-nicoles-mother-speaks/