From: Winnipeg, MB
Do what Ian R. has suggested. The base is connected by rail & road to Rangoon. Your supplies are automatically moved by the AI to places in need of supplies (same as US, Philippines, India, Australia, China, etc.) Additionally supplies into Burma will also feed into China (up to a set daily limit). The AI doesn't know that you want more supplies there, unless you do what Ian has suggested. Also check if you have other places in Burma set to stockpile, that may be competing for supply attention with the AI.
Any new player must acquaint themselves with Alfred's Logistics 101 which describes how and when supply moves over land.
No matter how bad a situation is, you can always make it worse. - Chris Hadfield : An Astronaut's Guide To Life On Earth