Macintosh bootable volumes are supported on the internal 2-port PCI card (part number TSATA) but are not supported on any of the other SATA cards at this time.
Often, yes. Sometimes, not. Some other manufacturers' drivers may incorrectly assume a Sonnet card is their SATA card which may cause havoc. The symptoms include significantly slower performance, driver not loading, or both drivers loading and causing and kernel panics as they both try to access the same card. Sonnet recommends removing other manufacturer's card(s) and driver(s) if a problem of this type occurs.
A Lion install removes the driver for the Tempo SATA E2P, Tempo SATA ExpressCard/34, and Tempo SATA edge ExpressCard/34. Just reinstall the driver and the card will work again.