First of all, many, many thanks to
Mind Forever Burning for his hard work on the Mac port.
Big news: We have a Mac version that is ready for testing. Once we've verified that it's working correctly, we'll update the page on cohtitan.com to reflect its availability.
http://cit.cohtitan.com/downloads/SentinelPlus.tgzIt should be as simple as dragging the app out of that archive into the folder that you want to save your characters into, then double-clicking the app while City of Heroes is running and you have the info window up. The OS should prompt for your credentials as it requires administrator access to run.
If you have the ability to test on both Mac and Windows, we would really appreciate it if you can try exporting the same character on both and verify that the files are the same. Failing that, if you want to test and don't mind putting your XML file somewhere accessible so we can take a look at it and make sure everything checks out, that would be helpful.