I've mixed E-TTL flashes and strobes many times with no problems. Make sure any optical triggering is disabled on the strobes, and use Pocket Wizards or a direct cable connection to fire them. The setup of the E-TTL flashes is the same; you can have a flash in the camera's hot shoe trigger other E-TTL flashes configured as slaves, regardless of whether strobes are involved or not. The image below shows 4 Alien Bee strobes, 4 Canon speedlights, and a Nikon SB-28DX all firing together:
[attachment=16566:MixedFlash.jpg]
The strobes and SB-28DX (the flash on the tripod) were triggered via a cable connected to the PC socket on the camera. The 3 Canon speedlights lying on the floor were triggered by a fourth Canon flash in the camera shoe, which is also illuminating my hand. Using your Profoto strobes instead of the Bees should work just as well.