No drivers need to be installed.
You need to download and install a program from Sony called "clip browser"
link below
Sony : XDCAM EX Clip Browsing Software V2.0 : United Kingdom
You import all the files from the EX1, either direclty from the camera via usb or from the cards themselves using a card reader.
The files need to be rewrapped to MXF using clip browser, ie, clips go from A to B being rewrapped to MXF in the process.
Then you can open Vegas (pro 8 needed) and just drag the files in as normal.
If an in depth workflow explanation is needed the just ask.
I use an EX1 and clip browser on an almost daily basis, since January.
The workflow is very simple and fast.
Paul.