Tokinsom , I'm not using the latest version, so I couldn't check your project, but accessing objects/properties from the tmx file should be relatively easy if you spend a little time getting familiar with XPath and how to access data from an xml file. I didn't know much about it prior to making that capx, and it was simple to figure out with a couple tutorials. I don't think you'd need to use javascript for any of the object/property stuff. The only reason why I had to use javascript was to change the way the tile data was structured.
If you're using the tmx importer, I'm not familiar with that, so I guess rexrainbow would need to check out how you're using it since I can't help you with that.