Hmm. I downloaded and installed the ov2 and bmp files (Starbucks, Quiznos and TimHortons) for Canada and dropped them into the folder for my map. (USA&Canada). I checked. They're all in the right place on the GPSs file structure within the Map folder & Using the TomTomHome software sees them as POIs with other factory optional POIs.
They also do show up in the POI menu when I boot up the TomTom. But if I select any of the custom POIs, the search returns : "No POI found!".
Am I missing something? Was there maybe a change in compatibility with Gen3?
PS: It's running Version 7.101 (not sure if that's the map or firmware)
TomTom One software for Gen3 has a bug. It is possible to patch it, but it is quite difficult to make it working. It can void your warranty if you decide to return it to seller.
It is much easier to replace your Gen3 with any other GPS device with better POI customization.