A first step of troubleshooting would be to find out whether Artist supports MMC.
If so a second step would be to figure out if your device sends the correct midi messages for MMC. One should not employ Cubase for this but a midi monitoring software like Midi Ox (Windows).
@Giannis_Agapakis, under Transport→Project Synchronization Setup you can find the options needed. As long of course, as @Johnny_Moneto already mentioned, the SL MK2 sends the proper messages (I think it does).