Most likely not related.
Soros has a proven aptitude at sending out feelers to involve himself in the internal matters of other countries, usually by sending in NGOs to form local alliances and buy politicians. However, this technique would not fly in China as they carefully watch foreign NGOs.
So in this case, they probably set up business ventures in Xilai’s city that on the surface were above board, but heavily supported so they were guaranteed to succeed. Then they let Xilai in on the deal, so he could get a piece of the action and claim credit for the success. It would also make his supporters happy by their getting low cost products.
The purpose of this was to ingratiate themselves with Xilai while at the same time making him look good so that he would ascend the political ladder.
Eventually, they were hoping that Xilai might become general party secretary, resulting in a huge ROI as they would have “the ear of the emperor”.
However, somehow part of the Chinese intelligence apparat figured out what was going on. Xilai himself probably got in the spotlight by embracing Cultural Revolution slogans, going politically radical before he had the juice (in his case ‘juche’? (NKor)) to do so.