General Motors (GM.N) and Chinese partner SAIC Motor Corp will soon announce a joint push into Indonesia, using their no-frills Wuling brand to establish a beachhead in Southeast Asia’s biggest market and from there tackle other markets in the region. They have already made moves to purchase a property in an industrial district on the outskirts of Jakarta, according to two people familiar with the matter, and are expected to detail within days what GM China chief Matt Tsien called an important joint venture in a country of 240 million people.