Rather than dealing with customer service, you might want to look at Andrew Wheeler's SFBC blog at
http://thebookblogger.com/sfbc/
You could probably contact Andrew directly there, or at least post a comment. If every new book SFBC announced had a comment asking when an electronic version was available, I'm sure they'd get the message pretty quick. In fact, I just posted such a comment on their latest acquisitions list at
http://thebookblogger.com/sfbc/2006/...n_novembe.html