Based on your other post (which shouldn't have suspected malware attached btw), you don't have an older variant of something, but you instead have something that McAfee doesn't currently detect.
If you have submitted it to McAfee, you should have a sample ID number returned to you via email or from the Webimmune system. What is the sample ID? Perhaps a McAfee Labs staff member can check on the submission.
Also, assuming you are supported by McAfee, log a Service Call and ask for the sample to be escalated due to it currently causing an Outbreak situation on your site.
The latest Beta dat does detect your sample -
Invitation Card\document.jpg .exe Generic.dx!osw
As for why no extra.dat, I can't answer that question.
Also, there is an extra.dat available via the "Generate an Extra.dat" page.
https://www.webimmune.net/extra/getextra.aspx (You would be requesting Generic.dx!osw
I assume you know how to install an extra.dat into Groupshield - if not, then there should be a technote regarding it in the serviceportal. I would direct you to it, but unsure of which version of Groupshield you are using.
Marking as 'assumed answered' due to age of thread. If you need any further assistance please don't hesitate to let us know.