I have a valid H1B visa though not stamped yet as I have not traveled to India since then. I got an invitation to speak at a conference in Spain next year. Am I eligible to get a schengen business visa? Is so, after conference I am aftraid I cannot re-enter US without stamping? Can I get it done in Spain or do I have to travel all the way to India, get it stamped and then enter US? Please advise?