KOREAN would like to apply for tourist visa in Phnom Phen

Hello,
I am Korean and visiting in China at the moment. I would like to visit Phnom Phen for a few days and will be back to China. However if I leave China once, my currently China tourist visa will be expired. So I have to ontain a tourist visa again before I go back to China. I would like to know if it is possible to obtain a multi- entry tourist visa with 12-month validity from the embassy in Phnom Penh. I don't have any residence visa for Cambodia but have a registration voucher of residence for visitors from overseas in China. Please advise.
Thank you.