I don't know if this will work for Windows 7, but I recently figured out how to get the 64MB Smart Card to work with Windows 8. Like you, I also had to find a Windows XP systems years ago but maybe this will help getting it to work on Windows 7. But what I had to do was use the driver signing program from Kitsch website to sign the drivers. Afterwards I booted Windows 8 in a mode that disabled the need for signed drivers. Then I plugged in the cart via USB and manually installed the driver. Windows 8 tried to say it wouldn't work, but it works fine.
The same might work for Windows 7, you just have to Google how to the disable signed driver utility.