The female gymnast who represented South Africa in the 2010 Commonwealth Games and won a silver medal in the Women's Gymnastics Vault event was Jennifer Khwela. She was a significant figure in South African gymnastics at the time, and her achievement was widely covered in the media. The search results also mention other gymnasts like Emily Little and Ashleigh Brennan from Australia, but they were not part of the South African team. There is no mention of other South African female gymnasts participating in the 2010 Commonwealth Games, suggesting that Jennifer Khwela was the sole representative or at least the most notable one. For more information, you can refer to the Wikipedia page on the Gymnastics at the 2010 Commonwealth Games.