I will be applying for Schengen visa from US mostly through German consulate. After the trip I will be returning back to US. I have a valid US visa stamp on my old passport, and that works with US immigration when entering into US. For Schengen visa, they check if I have valid documents for entering the next country after I depart from Schengen region. Can it be a problem in obtaining Schengen visa that my US visa stamp is on old passport?