I just created a custom property type which consist of two dates (published from and to) and an XForm. This XForm works fine and I can also see the statistics using the CMS Gadget.
But when I try to add the statistics on my page by adding a XFormStatistics-control from the CreateDefaultControls-method, I get an error telling me that the ExternalID can't be empty. I already set the PageLink and PageGuid properties. I also set the PropertyName, but I can imagine this is incorrect since the actual form is a subproperty fromt the actual property (being my custom property).
What am I doing wrong? Is it even possible to show statistics from an inner form of a custom property?
An extra note: I am adding the XForm to the page by using 'CreatePropertyControl' on the XForm-property and setting the PropertyData. I also noticed that in the database, all pageguids are empty for the data.