XFA Form to VB6 Host Communications

I have a VB6 application that hosts PDF forms designed using LiveCycle Designer 8. The VB6 application uses OLE Automation to load, display and interact with the form. The form is hosted in a VB6 standard form object. However, the form will need to able to get data from the VB6 application for events like button clicks, loading data into drop-down lists, validations, etc.
 
It uses this approach (in VB6) to load and display a PDF file:
 
...
Set AcroExchApp = CreateObject("AcroExch.App")
Set AcroExchAVDoc = CreateObject("AcroExch.AVDoc")
ok = AcroExchAVDoc.OpenInWindowEx(sFileName, Me.hWnd, CLng(AV_DOC_view), True, 0, CInt(PDUseNone), TmpViewMode, iZoomLevel, 0, 0)
 
If Not ok Then
MsgBox "Can't open file: " & sFileName, vbCritical, ""
Set AcroExchAVDoc = Nothing
Set AcroExchApp = Nothing
Exit Function
End If
 
Set AcroPDDoc = AcroExchAVDoc.GetPDDoc
Set AcroExchAVPageView = AcroExchAVDoc.GetAVPageView

Set jsObject = AcroPDDoc.GetJSObject
...
 
None of the AcroExch objects have any events exposed. How can I get my form to access methods or functions from within the VB6 application?
 
Is this possible and, if so, what is the preferred method to do this?