Hi, few weeks ago I have implemented custom code related to UPS, it's about creating shipments automatically from Drupal eCommerce platform when user buy certain product(s). It was for US client, too.
Also, I am familiar with UPS Drupal module and it's configuration, I know how it works and how to manage encryption or to handle various types of shipping options.
Do not hesitate to contact me in order to discuss other details, ask your questions or let me share my references. Time difference wouldn't be a problem, I can adapt on it.
I am almost 6 years experienced Drupal developer, 9 years in PHP.
Sincerely, Ratomir.