I downloaded and installed the 2010 ActiveX Beta version and everything is in Chinese. Using windows 7 and office 2010 all US English. There was only one file available on the downloads page.

I can add a new subchart in v8 ActiveX with:

TChart1.Tools.Tools.Add tcSubChart

but I cannot figure out how to refer to the subchart in code for adding series, data etc.

I had the same problem - cannot insert object onto Excel spreadsheet using v8 with v7 coexist. Deleting the TeeChart.exd file solved the problem.