Retrieving number of pages in a tiff

I am writing a program in VBA for outlook.
The program prompts the user when closing an email with an attachment and asks if they
would like to save the document. when storing the document I need to get the number of pages.

The code that I wrote is as follows:

Set AcroExchApp = CreateObject("AcroExch.App")
Set AcroExchPDDoc = CreateObject("AcroExch.PDDoc")
AcroExchPDDoc.Open strPath + aAttachments(i)
AcroExchPDDoc.GetNumPages

when the document is a pdf then it retrieves the number correctly, however when it is a tiff file
it always returns 0.
If you can get me any help with this i would greatly appreciate.
Thanks.

at a running guess I would say that tiff does not support GetNumPages as an action. Um... is there any other value you can pull at to get an estimate? Like length, size.... er... etc

why wouldnt it have that property if the document has a few pages?? and when I view it in imaging or adobe it shows the pages??

It was just a best guess, there is not the coheasive set of standards we would like there to be.