Since I decided to change from Vista x64 to Windows 7 Pro x64 I encountered the very same situation:
1. Neither Windows Update nor the "old" Soundblaster Driver seemed to recognize the Multimedia Audio controller (sorry if my translation does not reflect the precise device description) as the Soundblaster.
During my research I stumbled upon the fact that some "basic communication device" came out to be the gameport with is built onto the Soundboard itself.
Since Windows Vista, the gameport is not supported anymore, just to let you know. The solution which brought me on the path of identifying the device was to list the "Hardware ID". This information can be found when opening the device manager and opening the faulty device's preferences->Details->PulldownMenu->HardwareID. I copied the lowest situated, block in pieces into a search engine and voilą, here we go !
2. The solution which helped my when running XP x64 and Vista x64 was to get a hold of the x64 SB Audigy 24-bit driver (similar Audio Processor). This archive is known to be listed as SBAX_2_12_0001_20 holding the correct x64 drivers for the EMU10K Chip. When Installing the device everything went fine which made me confident. When running Winamp and selecting the "SB Live! Series" as output I heard the magnificent NOTHING.
It is commonly spread that one has to do some weird config in order to have the SB Live playing proper stereo Sound but I am not going into this, now. I tried this weird settings (7.1 Sound, diabling stuff....) but still no sound.
3. When reading about SB Live and Windows 7 x64 I found out that there are two alternative drivers which can be applied. One of them is the "Daniel_K" driver which is supposed to choke on >2GB RAM, the other one is the KxDriver. When installing the kxDriver (w/ admin rights) and explicitely following the instruction orders I found about 3 new devices in my sound config in Windows' control panel. Doing the trial-and-error method I achieved to have my Soundboard play sound (green jack->front speakers)
when I activated the "wave out 4/5" device.
Since I was 3ms before buying a Creative Xi-Fi gamer Soundboard with proper Windows 7 support, I now will transfer the costs for a case of beer
to the developer of KxDrivers, these guys did an awesome job !
Usage of 2 Soundboards: Virtual DJing :-)
Greets from Germany, Wurstschredder