it's worth noting that, if you've got a device that flat-out won't recognize in w7 - or any windows operating system, for that matter - but supposedly has driver support, you can force-install it through the device manager's hardware profiling service. if i'm not mistaken, there's an open-source asio driver that runs the blackjack, but i don't remember what it is. if i remember correctly, you're not getting advanced functionality, but it'll pass audio through both ways. the .inf for the system isn't correct since it's not designed for it, but you can make one and point it at the right files.
i'd use XP mode to see what files the driver uses (device manager, properties, device details, related files), then force-install those specific file names from the w7-compatible driver.
edit: first response on google outlines basically what i'd suggest doing. w7's interface isn't significantly different.