Column auto sort in Flex 2 DataGrid

Hi:

I'm using a DataGrid that feeds from a XML generated on PHP...It works just great...The problem is that columns get auto sorted alphabetically when the DataGrid shows up...How can I prevent that from happening???

FYI, I'm updating my Flex/PHP/SAP SE16 emulator...I got all columns but not in the same position that I'm sending them...I'm of course not specifiying COLUMNS...Just letting the DataGrid generate them for me -:)

Greetings,

Blag.