I'm pretty sure the Minibrute should sync automatically (to a fault, if you ask some people), so you will need to make sure your x0xb0x is set as clock master (not sure how to do that; I don't have one).
If you're sure the x0xb0x is set as master clock, and sync is still not working, I would next try power cycling the Minibrute with the midi in hooked up to the x0xb0x; the brute may need to find its clock source during a start-up cycle, though I don't think this is the case it is worth a shot.