I'm a project manager for a company that imports Granite/marble slabs. A lot of business is done with the country i came from so with my boss getting older, i could take the chance of going and inspect material, go to meetings/event,s etc.

All i sent for documents was a letter signed by my employer saying the need for me to go and why i was going. The process took about 3-4 weeks tops.

In Atlanta, they asked me dad's and mom's names (i guess to confirm identity), how long i stayed out of the country, reason for departure, type of work i did and that was pretty much it. Everything was smooth.

For you, my advice is to have your employer type up a letter and also send proof (course enrollment, registration, etc) that you are actually doing the specialization. Good luck!