Set oLines = oSession.AsObject(oBusObj.Lines)

retVal = oLines.MoveFirst()

do until oLines.EoF

' do stuff…

retVal = oLines.MoveNext()

loop ' oLines

I now get this error:

 Object doesn't support this property or method: 'oBusObj.Lines'

I've used that code block dozens of times... but I'm not sure if it will work for an invoice history button script.  Some things are restricted when you are in a read only object.

Well I AM only trying to read the detail lines. 

I've been able to read SO_InvoiceHeader and SO_InvoiceDetail data using similar logic, but I can't seem to get this to work at all for AR_Invoice_History

I did a quick test and the same thing happened to me.  I don't have an answer. 

In a rush I'd try AR_InvoiceHistoryInquiryDetail_bus (with browse filter) or ODBC... but maybe someone else has better suggestions.

Okay, I have found the solution and am posting it here for anyone else with the same problem:

oLines = oSession.GetObject ("AR_InvoiceHistoryInquiryDetail_bus")

if oLines <> 0 then

    Set oLines = oSession.AsObject (oLines)

End If

The trick was getting the correct object name, AR_InvoiceHistoryInquiryDetail_bus

Be sure to set a browse filter.  That is done automatically when created from the oSession object, but has to be done manually when creating a new object.

A little late but certain inquiry tasks do not actually have a Lines property like their entry tasks do which is why you get the error trying to reference that property.  

So getting your own handle works but as Kevin said, you need to set the browse filter yourself, which you should be able to use the header's oBusObj.GetKeyPadded() method plus the CHR function for the NULL character (0).  Whenever you use the browse filter functionality with mutli-part keys, all but the last segment needs to be NULL padded.  If all of your invoice numbers are 7 characters long, this in't an issue but should you have some where the invoice number is less than 7 (the max length for the invoice number field) characters, then your browse filter will fail.