DomieGre, the iLiad companion software is designed for use for Windows XP and it also doesn't merge notes in a PDF.
You'll have to download the scribble merger program from iRex and install that on your PC.
http://support.irexnet.com/index.php...id=23&nav=0,17
With this tool, you can merge your scribbles made on a PDF on the iLiad into a single PDF document on your PC.