I would talk to my sewing machine dealer but I vaguely remember doing this a long time ago. I wound the elastic thread very slowly onto the bobbin by hand. I have a second bobbin case for my machine that I adjust the tension on for specialty threads.
Some people call this a form of smocking and some will call it shirring. Here's a set of instructions I found from someone. I haven't used these particular ones myself but they might help.
http://sewing.patternreview.com/cgi-...iew.pl?ID=1601