Don't know if anyone has mentioned this but there is a very cheap adapter available that might solve the problem


http://cgi.ebay.com/PRESTA-VALVE-TO-SCHRADER-ADAPTOR-BIKE-TUBE-FRENCH_W0QQitemZ370112191030QQcmdZViewItemQQptZCycling_Parts_Accessories?hash=item370112191030&_trksid=p3286.c0.m14&_trkparms=72%3A1205|66%3A4|65%3A12|39%3A1|240%3A1318