How do we know what characters correspond to Chinese names? Recently I've asked "How do we choose the correct characters for a westerner name?", and now, I'm facing a similar, yet kind of different problem, which I think applies to any westerner or Chinese student at a beginner level. 

There are two exercises that ask to translate some sentences, which are not that hard, thanks to the glossary, but I've faced a small, nonetheless daunting difficulty, which is the translation of Chinese names.

When I have to translate a sentence like "Mr. Hu/Huang/... is a lawyer", how do I know which character corresponds to that name? Are there any guidelines for selecting the right character (apart from asking the person directly)?
This is actually a common problem in newspapers and television in Singapore, where the original report may have been filed by a reporter who did not or cannot use Chinese. In these cases, the author simply chooses phonetically matching characters to fill in the name of the person, then add (音) or (译音) to indicate that the name shown is only a phonetic translation of the person's name and not the actual characters. 

An example can be found in this article from the local newspaper 《联合早报》


  被告谢国安（26岁，译音）共面对12项控状，包括四项冒充欺骗、两项麻醉物法令、三项偷窃，以及欺骗、失信和伤人罪状各一项。昨天他被判坐牢1年又10个月。