How to determine if Transition pack is installed on SBS

As part of an assessment recently I needed to know if a client had the Transition Pack installed on their Small Business Server – this allows the client to have more than 75 users/devices connected to the server. They were not aware that they had purchased the transition pack (and as it’s expensive I would imagine they would know they have purchased it) yet it looked like they had more than 75 user/devices.
Looking online there didn’t seem to be any information on how to tell if the pack had been purchased and as it is not something you can download and try, it wasn’t possible to just see what happens if it was installed. I also didn’t want to suggest that they purchase the software if they already had and it was already installed.
I put a call into Microsoft to find out how to tell if the Transition Pack is installed and the answer is obvious if you think about it, but it doesn’t scream out “Transaction Pack”.
It would have been nice if it appeared in the Add/Remove Programs but it doesn’t. It can appear as a product id but the absence of the id doesn’t always imply that it hasn’t been installed.
Instead the way to tell is to go into Add/Remove Programs, Windows Components and then see if it is possible to change Terminal Services to application mode. SBS does not support this mode but Windows 2003 does. Obvious now you know the answer, but not an obvious solution if you didn’t know the answer.