Its true! you should be very careful in bringing your sister here if u doesn't sure what will happen to her since she's on business/visit visa. Sometimes, the ministry are questioning this type of visa, but somes are lucky they passed through it. Its better try to apply her on the immigration as a family visit visa, since she's your sister, right? and it could be best for both of you coz they are giving atleast 3-6 months renewable, compared to business visa which is on limited period of time.And it can easily transfer to a working visa once she got her job.And based on my experiences, failed to transfered visa for my brother under the same visa as u mentioned, because they always changing the rules every now and then. He went back to Philippines but after 3 months i applied on the immigration for a visit visa for him, and now he's 7 months working in one prestigious company here...In short, go for the immigration and apply there.........best regards