I know it has been a long time since your question was posted, but thought I would let you know what I was able to research for my own tree. I found a family history on Google on the Beverhoudt family in St Croix. They show a Helene Beverhoudt (she also was listed as Neeltje) and William Mac Dougall are the parents of Dr William Mac Dougall, Plantageejer (planter) , on St Croix. The record is in Dutch. I am still searching for information on him owning a plantation. I know there are other trees that show some of the relatives had slaves. Please let me know if you find any other information.