I also had the problem of the Windows 7 Installation finding the 3114 and it was eventually solved here:
Silicon Image - Support | Search Results
Product Searched for: SiI3114 - PCI to 4 Port SATA150
Next, get the SiI3114 64-bit Windows 7 SATARAID5 Driver - 2/9/2010 - ver. 1.5.20.3
or the SiI3114 32-bit Windows SATARAID5 Driver - 2/9/2010 - ver. 1.5.20.3
Then, burn these files onto a CD or USB drive and chose "Load Driver". It then scans and finds si3114r5.inf, after clicking Next, choose Refresh. You will then see a message "Windows cannot be installed to... and/or Error 0x8030001 Simply swap the driver CD out and place the Windows 7 Installation disc back in and try again and then installation will continue from there. (I did this on CD - a USB drive will probably work better)