Two options;
1. You ask the school to have the I20 (visa application form) include the dates of hour building, which is not really necessary.
2.On a M1 visa you can enter the country up to 30 days before the start date of your course as stated on the visa.Use this time for your hour building.
Reason being that M1 is a student visa and it allows you time to enter the country, find accomodation,get your study materials, get familiar with your school etc etc before the course actually starts.
*****I am not a visa specialist, so one call to the embassy will clarify this.****