Rugger,
I was able to find a driver for your HP E3631A on our web site. If you go to http://search.ni.com/query.html?lk=1&nh=500&rf=3&ql=&pw=595&qp=%2BContentType%3AInstrumentDriver+%2BIDNetInstrumentType%3A%22Power+Supplies%22+%2BIDNetManufacturer%3A%22Hewlett-Packard%2C+Agilent+Technologies%22&qt=3631&layout=IDNet, the link will lead you to the web page. You can also find other drivers yourself by going to www.ni.com >> technical support >> option 3: Instrument drivers >> Downloads >> and enter your search criteria.
Regards,
Sarah Fenney
Applications Engineer